diff --git a/core/src/sync/client.rs b/core/src/sync/client.rs
index 62015b8..39809a9 100644
--- a/core/src/sync/client.rs
+++ b/core/src/sync/client.rs
@@ -439,19 +439,59 @@ pub struct Member {
     pub email: String,
 }
 
-/// One person a note is shared with, and at what level (`view` or `edit`).
+/// A group the admin made, which a note can be shared with (#5177). Sharing with it
+/// reaches whoever is in it at the time.
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
+pub struct ShareGroup {
+    pub id: String,
+    #[serde(default)]
+    pub name: String,
+    #[serde(default)]
+    pub member_count: u32,
+}
+
+/// Everyone a note can be shared with: the other people on the instance, and every
+/// group. `groups` defaults empty for a server from before groups.
+#[derive(Debug, Clone, Default, Deserialize, Serialize, PartialEq, Eq)]
+pub struct Directory {
+    #[serde(default)]
+    pub members: Vec<Member>,
+    #[serde(default)]
+    pub groups: Vec<ShareGroup>,
+}
+
+/// One share of a note, at `view` or `edit`: to a person (`member`) or to a group
+/// (`group`), never both.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
 pub struct NoteShare {
     pub id: String,
-    pub member: Member,
+    #[serde(default)]
+    pub member: Option<Member>,
+    #[serde(default)]
+    pub group: Option<ShareGroup>,
     pub permission: String,
     #[serde(default)]
     pub created_at: Option<String>,
 }
 
-#[derive(Deserialize)]
-struct MembersReply {
-    members: Vec<Member>,
+/// Who a new share goes to.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ShareTarget {
+    Member(String),
+    Group(String),
+}
+
+impl ShareTarget {
+    fn body(&self, permission: &str) -> serde_json::Value {
+        match self {
+            ShareTarget::Member(id) => {
+                serde_json::json!({ "user_id": id, "permission": permission })
+            }
+            ShareTarget::Group(id) => {
+                serde_json::json!({ "group_id": id, "permission": permission })
+            }
+        }
+    }
 }
 
 #[derive(Deserialize)]
@@ -493,11 +533,10 @@ async fn read_reply<T: serde::de::DeserializeOwned>(
         .map_err(|e| format!("Couldn't read the reply from {base_url}: {e}"))
 }
 
-/// Everyone on the instance but this account.
-pub async fn directory(base_url: &str, token: &str) -> Result<Vec<Member>, String> {
+/// Everyone on the instance but this account, and every group.
+pub async fn directory(base_url: &str, token: &str) -> Result<Directory, String> {
     let url = format!("{base_url}/api/users/directory");
-    let reply: MembersReply = read_reply(base_url, prepare(http()?.get(url), Some(token))).await?;
-    Ok(reply.members)
+    read_reply(base_url, prepare(http()?.get(url), Some(token))).await
 }
 
 pub async fn list_shares(
@@ -510,16 +549,17 @@ pub async fn list_shares(
     Ok(reply.shares)
 }
 
-/// Share with one member, or change their permission. Answers the note's shares.
+/// Share with a person or a group, or change their permission. Answers the note's
+/// shares.
 pub async fn share_note(
     base_url: &str,
     token: &str,
     note_id: &str,
-    user_id: &str,
+    target: &ShareTarget,
     permission: &str,
 ) -> Result<Vec<NoteShare>, String> {
     let url = format!("{base_url}/api/notes/{note_id}/shares");
-    let body = serde_json::json!({ "user_id": user_id, "permission": permission });
+    let body = target.body(permission);
     let reply: SharesReply = read_reply(
         base_url,
         prepare(http()?.post(url), Some(token)).json(&body),
@@ -583,6 +623,27 @@ fn describe_transport_error(base_url: &str, err: &reqwest::Error) -> String {
 mod tests {
     use super::*;
 
+    #[test]
+    fn a_share_names_a_person_or_a_group() {
+        assert_eq!(
+            ShareTarget::Member("u1".into()).body("view"),
+            serde_json::json!({ "user_id": "u1", "permission": "view" })
+        );
+        assert_eq!(
+            ShareTarget::Group("g1".into()).body("edit"),
+            serde_json::json!({ "group_id": "g1", "permission": "edit" })
+        );
+        let raw = r#"{"id":"s2","member":null,
+                      "group":{"id":"g1","name":"Family","member_count":3},
+                      "permission":"edit"}"#;
+        let share: NoteShare = serde_json::from_str(raw).expect("a group share reads");
+        assert!(share.member.is_none());
+        assert_eq!(share.group.expect("group").member_count, 3);
+        // A server from before groups sends no `groups` at all.
+        let older: Directory = serde_json::from_str(r#"{"members":[]}"#).expect("directory");
+        assert!(older.groups.is_empty());
+    }
+
     #[test]
     fn urls_join_without_doubling_slashes() {
         // normalize_base_url has already stripped any trailing slash, so plain
diff --git a/core/src/sync/sharing.rs b/core/src/sync/sharing.rs
index 9755b1f..8271e73 100644
--- a/core/src/sync/sharing.rs
+++ b/core/src/sync/sharing.rs
@@ -8,7 +8,7 @@
 
 use rusqlite::params;
 
-use super::client::{self, Member, NoteShare};
+use super::client::{self, Directory, NoteShare, ShareTarget};
 use super::state;
 use crate::local::Db;
 
@@ -38,7 +38,7 @@ fn mark_shared(db: &Db, note_id: &str, shares: &[NoteShare]) -> Result<(), Strin
     Ok(())
 }
 
-pub async fn directory(db: &Db) -> Result<Vec<Member>, String> {
+pub async fn directory(db: &Db) -> Result<Directory, String> {
     let (url, token) = link(db)?;
     client::directory(&url, &token).await
 }
@@ -53,11 +53,11 @@ pub async fn list(db: &Db, note_id: &str) -> Result<Vec<NoteShare>, String> {
 pub async fn share(
     db: &Db,
     note_id: &str,
-    user_id: &str,
+    target: &ShareTarget,
     permission: &str,
 ) -> Result<Vec<NoteShare>, String> {
     let (url, token) = link(db)?;
-    let shares = client::share_note(&url, &token, note_id, user_id, permission).await?;
+    let shares = client::share_note(&url, &token, note_id, target, permission).await?;
     mark_shared(db, note_id, &shares)?;
     Ok(shares)
 }
@@ -73,6 +73,7 @@ pub async fn unshare(db: &Db, note_id: &str, share_id: &str) -> Result<Vec<NoteS
 mod tests {
     use super::*;
     use crate::local::schema;
+    use crate::sync::client::Member;
     use rusqlite::Connection;
     use std::sync::Mutex;
 
@@ -101,11 +102,12 @@ mod tests {
         }
         let one = NoteShare {
             id: "s1".into(),
-            member: Member {
+            member: Some(Member {
                 id: "u2".into(),
                 display_name: "Sam".into(),
                 email: "sam@example.test".into(),
-            },
+            }),
+            group: None,
             permission: "view".into(),
             created_at: None,
         };
diff --git a/desktop/src-tauri/src/commands/sync.rs b/desktop/src-tauri/src/commands/sync.rs
index b6c6ebc..d1a2419 100644
--- a/desktop/src-tauri/src/commands/sync.rs
+++ b/desktop/src-tauri/src/commands/sync.rs
@@ -8,7 +8,7 @@ use tauri::{AppHandle, State};
 
 use inkwell_core::local::Db;
 use inkwell_core::sync::client::{self, Identity, ProbeResult};
-use inkwell_core::sync::client::{Member, NoteShare};
+use inkwell_core::sync::client::{Directory, NoteShare, ShareTarget};
 use inkwell_core::sync::compat::Compatibility;
 use inkwell_core::sync::engine;
 use inkwell_core::sync::push;
@@ -193,7 +193,7 @@ pub fn sync_has_pending(db: State<'_, Db>) -> Result<bool, String> {
 // `sharing::NEEDS_SERVER`, which the dialog shows as it is.
 
 #[tauri::command]
-pub async fn shares_directory(db: State<'_, Db>) -> Result<Vec<Member>, String> {
+pub async fn shares_directory(db: State<'_, Db>) -> Result<Directory, String> {
     sharing::directory(&db).await
 }
 
@@ -202,14 +202,21 @@ pub async fn shares_list(note_id: String, db: State<'_, Db>) -> Result<Vec<NoteS
     sharing::list(&db, &note_id).await
 }
 
+/// Share with a person (`user_id`) or a group (`group_id`, #5177): exactly one.
 #[tauri::command]
 pub async fn shares_share(
     note_id: String,
-    user_id: String,
+    user_id: Option<String>,
+    group_id: Option<String>,
     permission: String,
     db: State<'_, Db>,
 ) -> Result<Vec<NoteShare>, String> {
-    sharing::share(&db, &note_id, &user_id, &permission).await
+    let target = match (user_id, group_id) {
+        (Some(id), None) => ShareTarget::Member(id),
+        (None, Some(id)) => ShareTarget::Group(id),
+        _ => return Err("Choose someone or a group to share with.".to_string()),
+    };
+    sharing::share(&db, &note_id, &target, &permission).await
 }
 
 #[tauri::command]
diff --git a/frontend/src/adapters/local.ts b/frontend/src/adapters/local.ts
index 851cb34..5034076 100644
--- a/frontend/src/adapters/local.ts
+++ b/frontend/src/adapters/local.ts
@@ -16,7 +16,7 @@ import type { Device } from "../stores/devices";
 import type { TitleEntry } from "../stores/titles";
 import type { User } from "../stores/session";
 import type { PublicConfig } from "../stores/config";
-import type { DeviceToken, ImportResult, Member, NoteShare, Repo } from "./repo";
+import type { DeviceToken, Directory, ImportResult, NoteShare, Repo } from "./repo";
 
 const NEEDS_SERVER = "That's not available offline — connect a server to use it.";
 
@@ -95,9 +95,15 @@ export const local: Repo = {
   // Sharing is between accounts on a server, so these go to the linked one (#5175).
   // Unlinked, each rejects with the core's explanation, which the dialog shows.
   shares: {
-    directory: () => invoke<Member[]>("shares_directory"),
+    directory: () => invoke<Directory>("shares_directory"),
     list: (noteId) => invoke<NoteShare[]>("shares_list", { noteId }),
-    share: (noteId, userId, permission) => invoke<NoteShare[]>("shares_share", { noteId, userId, permission }),
+    share: (noteId, target, permission) =>
+      invoke<NoteShare[]>("shares_share", {
+        noteId,
+        userId: "user_id" in target ? target.user_id : null,
+        groupId: "group_id" in target ? target.group_id : null,
+        permission,
+      }),
     unshare: (noteId, shareId) => invoke<NoteShare[]>("shares_unshare", { noteId, shareId }),
   },
 };
diff --git a/frontend/src/adapters/repo.ts b/frontend/src/adapters/repo.ts
index 0705674..4efed3e 100644
--- a/frontend/src/adapters/repo.ts
+++ b/frontend/src/adapters/repo.ts
@@ -55,11 +55,29 @@ export interface Member {
   email: string;
 }
 
+/** A group the admin made, as the directory shows it (#5177). */
+export interface ShareGroup {
+  id: string;
+  name: string;
+  member_count: number;
+}
+
+/** Everyone a note can be shared with: the other people, and every group. */
+export interface Directory {
+  members: Member[];
+  groups: ShareGroup[];
+}
+
+/** Who a share goes to: one person, or a group (whoever is in it at the time). */
+export type ShareTarget = { user_id: string } | { group_id: string };
+
 export type SharePermission = "view" | "edit";
 
+/** One share of a note: exactly one of `member` and `group` is set. */
 export interface NoteShare {
   id: string;
-  member: Member;
+  member: Member | null;
+  group: ShareGroup | null;
   permission: SharePermission;
   created_at: string | null;
 }
@@ -135,11 +153,11 @@ export interface NotesRepo {
 }
 
 export interface SharesRepo {
-  /** Everyone on the instance but you. */
-  directory(): Promise<Member[]>;
+  /** Everyone on the instance but you, and every group. */
+  directory(): Promise<Directory>;
   list(noteId: string): Promise<NoteShare[]>;
-  /** Share with one member, or change their permission. Answers the note's shares. */
-  share(noteId: string, userId: string, permission: SharePermission): Promise<NoteShare[]>;
+  /** Share with a person or a group, or change their permission. Answers the note's shares. */
+  share(noteId: string, target: ShareTarget, permission: SharePermission): Promise<NoteShare[]>;
   unshare(noteId: string, shareId: string): Promise<NoteShare[]>;
 }
 
diff --git a/frontend/src/adapters/rest.ts b/frontend/src/adapters/rest.ts
index d3fd680..72055f9 100644
--- a/frontend/src/adapters/rest.ts
+++ b/frontend/src/adapters/rest.ts
@@ -14,8 +14,8 @@ import type { User } from "../stores/session";
 import type { PublicConfig } from "../stores/config";
 import type {
   DeviceToken,
+  Directory,
   ImportResult,
-  Member,
   NoteChanges,
   NoteShare,
   NoteCreateInput,
@@ -120,10 +120,10 @@ export const rest: Repo = {
   },
 
   shares: {
-    directory: async () => (await api.get<{ members: Member[] }>("/api/users/directory")).members,
+    directory: () => api.get<Directory>("/api/users/directory"),
     list: async (noteId) => (await api.get<{ shares: NoteShare[] }>(`/api/notes/${noteId}/shares`)).shares,
-    share: async (noteId, userId, permission) =>
-      (await api.post<{ shares: NoteShare[] }>(`/api/notes/${noteId}/shares`, { user_id: userId, permission })).shares,
+    share: async (noteId, target, permission) =>
+      (await api.post<{ shares: NoteShare[] }>(`/api/notes/${noteId}/shares`, { ...target, permission })).shares,
     unshare: async (noteId, shareId) =>
       (await api.del<{ shares: NoteShare[] }>(`/api/notes/${noteId}/shares/${shareId}`)).shares,
   },
diff --git a/frontend/src/components/GroupList.vue b/frontend/src/components/GroupList.vue
new file mode 100644
index 0000000..3e2c3ed
--- /dev/null
+++ b/frontend/src/components/GroupList.vue
@@ -0,0 +1,228 @@
+<script setup lang="ts">
+import { computed, onMounted, ref } from "vue";
+import { api } from "../api/client";
+import { errorMessage } from "../api/errors";
+import { useUiStore } from "../stores/ui";
+import BaseButton from "./BaseButton.vue";
+import BaseInput from "./BaseInput.vue";
+import Icon from "./Icon.vue";
+
+// Admin: groups of people a note can be shared with in one go (#5177). A group is
+// the instance's; anyone can share with it, and a note shared with it reaches whoever
+// is in it at the time, so adding or removing someone here changes what they see.
+
+interface Person {
+  id: string;
+  display_name: string;
+  email: string;
+}
+
+interface Group {
+  id: string;
+  name: string;
+  members: Person[];
+}
+
+const ui = useUiStore();
+
+const groups = ref<Group[]>([]);
+const accounts = ref<Person[]>([]);
+const loading = ref(true);
+const error = ref("");
+const name = ref("");
+const creating = ref(false);
+const busy = ref("");
+// Which group's "Add someone" picker holds which account id.
+const picks = ref<Record<string, string>>({});
+
+const byName = (a: Group, b: Group) => a.name.localeCompare(b.name);
+
+function outside(group: Group): Person[] {
+  const inside = new Set(group.members.map((m) => m.id));
+  return accounts.value.filter((a) => !inside.has(a.id));
+}
+
+const empty = computed(() => !loading.value && !groups.value.length);
+
+async function load() {
+  error.value = "";
+  try {
+    const [g, a] = await Promise.all([
+      api.get<{ groups: Group[] }>("/api/groups"),
+      api.get<{ accounts: Person[] }>("/api/accounts"),
+    ]);
+    groups.value = g.groups;
+    accounts.value = a.accounts;
+  } catch (e) {
+    error.value = errorMessage(e, "Couldn't load groups.");
+  } finally {
+    loading.value = false;
+  }
+}
+
+function replace(updated: Group) {
+  groups.value = groups.value.map((g) => (g.id === updated.id ? updated : g)).sort(byName);
+}
+
+async function act(id: string, fn: () => Promise<void>, fallback: string) {
+  busy.value = id;
+  try {
+    await fn();
+  } catch (e) {
+    ui.showToast(errorMessage(e, fallback));
+  } finally {
+    busy.value = "";
+  }
+}
+
+async function create() {
+  if (!name.value.trim()) return;
+  creating.value = true;
+  error.value = "";
+  try {
+    const made = await api.post<Group>("/api/groups", { name: name.value.trim() });
+    groups.value = [...groups.value, made].sort(byName);
+    name.value = "";
+  } catch (e) {
+    error.value = errorMessage(e, "Couldn't create the group.");
+  } finally {
+    creating.value = false;
+  }
+}
+
+function rename(group: Group) {
+  const next = window.prompt("Rename the group", group.name)?.trim();
+  if (!next || next === group.name) return;
+  void act(
+    group.id,
+    async () => replace(await api.patch<Group>(`/api/groups/${group.id}`, { name: next })),
+    "Couldn't rename it.",
+  );
+}
+
+function remove(group: Group) {
+  if (!window.confirm(`Delete "${group.name}"? Notes shared with it stop being shared with its members.`)) return;
+  void act(
+    group.id,
+    async () => {
+      await api.del(`/api/groups/${group.id}`);
+      groups.value = groups.value.filter((g) => g.id !== group.id);
+    },
+    "Couldn't delete it.",
+  );
+}
+
+function addMember(group: Group) {
+  const userId = picks.value[group.id];
+  if (!userId) return;
+  void act(
+    group.id,
+    async () => {
+      replace(await api.post<Group>(`/api/groups/${group.id}/members`, { user_id: userId }));
+      picks.value[group.id] = "";
+    },
+    "Couldn't add them.",
+  );
+}
+
+function removeMember(group: Group, person: Person) {
+  void act(
+    group.id,
+    async () => replace(await api.del<Group>(`/api/groups/${group.id}/members/${person.id}`)),
+    "Couldn't remove them.",
+  );
+}
+
+onMounted(() => {
+  void load();
+});
+</script>
+
+<template>
+  <section class="flex flex-col gap-5">
+    <h2 class="text-xs font-semibold uppercase tracking-wide text-neutral-400">Groups</h2>
+
+    <form class="flex flex-wrap items-end gap-3" @submit.prevent="create">
+      <BaseInput id="group-name" v-model="name" label="New group" placeholder="Family" class="min-w-48 flex-1" />
+      <BaseButton type="submit" :loading="creating" :disabled="!name.trim()">Create group</BaseButton>
+    </form>
+
+    <p v-if="error" class="text-sm text-red-600 dark:text-red-400">{{ error }}</p>
+
+    <div v-if="loading" class="py-6 text-center text-sm text-neutral-400">Loading…</div>
+    <p v-else-if="empty" class="text-sm text-neutral-400">No groups yet.</p>
+    <ul v-else class="flex flex-col gap-2">
+      <li
+        v-for="g in groups"
+        :key="g.id"
+        class="flex flex-col gap-3 rounded-xl border border-neutral-200 px-4 py-3 dark:border-neutral-800"
+      >
+        <div class="flex items-center justify-between gap-4">
+          <div class="min-w-0">
+            <p class="truncate text-sm font-medium text-neutral-800 dark:text-neutral-100">{{ g.name }}</p>
+            <p class="text-xs text-neutral-400">
+              {{ g.members.length }} {{ g.members.length === 1 ? "person" : "people" }}
+            </p>
+          </div>
+          <div class="flex shrink-0 items-center gap-2">
+            <button
+              type="button"
+              class="rounded-md border border-neutral-300 px-2.5 py-1 text-xs text-neutral-700 hover:bg-neutral-100 focus:outline-none focus-visible:ring-2 focus-visible:ring-brand disabled:opacity-50 dark:border-neutral-700 dark:text-neutral-200 dark:hover:bg-neutral-800"
+              :disabled="busy === g.id"
+              @click="rename(g)"
+            >
+              Rename
+            </button>
+            <button
+              type="button"
+              class="rounded-md border border-neutral-300 px-2.5 py-1 text-xs text-red-600 hover:bg-red-50 focus:outline-none focus-visible:ring-2 focus-visible:ring-brand disabled:opacity-50 dark:border-neutral-700 dark:text-red-400 dark:hover:bg-red-950/40"
+              :disabled="busy === g.id"
+              @click="remove(g)"
+            >
+              Delete
+            </button>
+          </div>
+        </div>
+
+        <ul v-if="g.members.length" class="flex flex-wrap gap-1.5">
+          <li
+            v-for="m in g.members"
+            :key="m.id"
+            class="flex items-center gap-1 rounded-full bg-neutral-100 py-0.5 pl-2.5 pr-1 text-xs text-neutral-700 dark:bg-neutral-800 dark:text-neutral-200"
+            :title="m.email"
+          >
+            {{ m.display_name || m.email }}
+            <button
+              type="button"
+              class="rounded-full p-0.5 text-neutral-400 hover:text-red-500 disabled:opacity-50"
+              :aria-label="`Remove ${m.display_name || m.email} from ${g.name}`"
+              :disabled="busy === g.id"
+              @click="removeMember(g, m)"
+            >
+              <Icon name="close" />
+            </button>
+          </li>
+        </ul>
+
+        <form v-if="outside(g).length" class="flex flex-wrap items-center gap-2" @submit.prevent="addMember(g)">
+          <select
+            v-model="picks[g.id]"
+            class="min-w-0 flex-1 rounded-md border border-neutral-300 bg-white px-2 py-1.5 text-sm outline-none focus-visible:ring-2 focus-visible:ring-brand dark:border-neutral-700 dark:bg-neutral-800"
+            :aria-label="`Add someone to ${g.name}`"
+            :disabled="busy === g.id"
+          >
+            <option :value="undefined" disabled>Add someone…</option>
+            <option v-for="a in outside(g)" :key="a.id" :value="a.id">{{ a.display_name }} ({{ a.email }})</option>
+          </select>
+          <button
+            type="submit"
+            class="rounded-md border border-neutral-300 px-2.5 py-1.5 text-xs text-neutral-700 hover:bg-neutral-100 focus:outline-none focus-visible:ring-2 focus-visible:ring-brand disabled:opacity-50 dark:border-neutral-700 dark:text-neutral-200 dark:hover:bg-neutral-800"
+            :disabled="busy === g.id || !picks[g.id]"
+          >
+            Add
+          </button>
+        </form>
+      </li>
+    </ul>
+  </section>
+</template>
diff --git a/frontend/src/components/ShareDialog.vue b/frontend/src/components/ShareDialog.vue
index 62119d8..4e25617 100644
--- a/frontend/src/components/ShareDialog.vue
+++ b/frontend/src/components/ShareDialog.vue
@@ -1,15 +1,16 @@
 <script setup lang="ts">
 import { computed, onMounted, ref } from "vue";
 import { repo } from "../adapters";
-import type { Member, NoteShare, SharePermission } from "../adapters/repo";
+import type { Directory, NoteShare, SharePermission, ShareTarget } from "../adapters/repo";
 import { errorMessage } from "../api/errors";
 import { useNotesStore } from "../stores/notes";
 import BaseModal from "./BaseModal.vue";
 import Icon from "./Icon.vue";
 
-// Share a note with other people on this instance (#5174). The owner picks a member
-// from the directory and says whether they may only read it or also change its text.
-// Only the owner opens this; the server refuses everyone else regardless.
+// Share a note with other people on this instance (#5174). The owner picks a member,
+// or a group the admin made (#5177), and says whether they may only read it or also
+// change its text. Only the owner opens this; the server refuses everyone else
+// regardless.
 
 const props = defineProps<{ noteId: string }>();
 const emit = defineEmits<{ (e: "close"): void }>();
@@ -20,26 +21,47 @@ const PERMISSIONS: { value: SharePermission; label: string }[] = [
   { value: "edit", label: "Can edit" },
 ];
 
-const members = ref<Member[]>([]);
+const directory = ref<Directory>({ members: [], groups: [] });
 const shares = ref<NoteShare[]>([]);
 const loading = ref(true);
 const loadError = ref("");
 const error = ref("");
 const busy = ref(false);
+// "u:<id>" for a person, "g:<id>" for a group: one picker lists both.
 const pick = ref("");
 const permission = ref<SharePermission>("view");
 
-/** The people it isn't shared with yet. */
-const available = computed(() => {
-  const taken = new Set(shares.value.map((s) => s.member.id));
-  return members.value.filter((m) => !taken.has(m.id));
+/** The people and groups it isn't shared with yet. */
+const availablePeople = computed(() => {
+  const taken = new Set(shares.value.map((s) => s.member?.id));
+  return directory.value.members.filter((m) => !taken.has(m.id));
 });
+const availableGroups = computed(() => {
+  const taken = new Set(shares.value.map((s) => s.group?.id));
+  return directory.value.groups.filter((g) => !taken.has(g.id));
+});
+const anyone = computed(() => directory.value.members.length + directory.value.groups.length > 0);
+const anyoneLeft = computed(() => availablePeople.value.length + availableGroups.value.length > 0);
+
+function targetOf(share: NoteShare): ShareTarget {
+  return share.group ? { group_id: share.group.id } : { user_id: share.member?.id ?? "" };
+}
+
+function nameOf(share: NoteShare): string {
+  return share.group?.name ?? share.member?.display_name ?? "";
+}
+
+function detailOf(share: NoteShare): string {
+  if (!share.group) return share.member?.email ?? "";
+  const n = share.group.member_count;
+  return `Group · ${n} ${n === 1 ? "person" : "people"}`;
+}
 
 async function load() {
   loading.value = true;
   loadError.value = "";
   try {
-    [members.value, shares.value] = await Promise.all([repo.shares.directory(), repo.shares.list(props.noteId)]);
+    [directory.value, shares.value] = await Promise.all([repo.shares.directory(), repo.shares.list(props.noteId)]);
   } catch (e) {
     loadError.value = errorMessage(e, "Couldn't load who this is shared with.");
   } finally {
@@ -62,13 +84,14 @@ async function run(fn: () => Promise<NoteShare[]>, fallback: string) {
 
 async function add() {
   if (!pick.value) return;
-  const userId = pick.value;
-  await run(() => repo.shares.share(props.noteId, userId, permission.value), "Couldn't share the note.");
+  const id = pick.value.slice(2);
+  const target: ShareTarget = pick.value.startsWith("g:") ? { group_id: id } : { user_id: id };
+  await run(() => repo.shares.share(props.noteId, target, permission.value), "Couldn't share the note.");
   if (!error.value) pick.value = "";
 }
 
 function change(share: NoteShare, next: SharePermission) {
-  void run(() => repo.shares.share(props.noteId, share.member.id, next), "Couldn't change that.");
+  void run(() => repo.shares.share(props.noteId, targetOf(share), next), "Couldn't change that.");
 }
 
 function remove(share: NoteShare) {
@@ -103,14 +126,23 @@ onMounted(load);
       </div>
 
       <template v-else>
-        <p v-if="!members.length" class="text-sm text-neutral-500 dark:text-neutral-400">
+        <p v-if="!anyone" class="text-sm text-neutral-500 dark:text-neutral-400">
           No one else has an account here yet. An admin can invite people from Settings.
         </p>
 
-        <form v-else-if="available.length" class="flex flex-wrap items-center gap-2" @submit.prevent="add">
-          <select v-model="pick" :class="[selectClass, 'min-w-0 flex-1']" aria-label="Person" :disabled="busy">
+        <form v-else-if="anyoneLeft" class="flex flex-wrap items-center gap-2" @submit.prevent="add">
+          <select v-model="pick" :class="[selectClass, 'min-w-0 flex-1']" aria-label="Person or group" :disabled="busy">
             <option value="" disabled>Choose someone…</option>
-            <option v-for="m in available" :key="m.id" :value="m.id">{{ m.display_name }} ({{ m.email }})</option>
+            <optgroup v-if="availablePeople.length" label="People">
+              <option v-for="m in availablePeople" :key="m.id" :value="`u:${m.id}`">
+                {{ m.display_name }} ({{ m.email }})
+              </option>
+            </optgroup>
+            <optgroup v-if="availableGroups.length" label="Groups">
+              <option v-for="g in availableGroups" :key="g.id" :value="`g:${g.id}`">
+                {{ g.name }} ({{ g.member_count }})
+              </option>
+            </optgroup>
           </select>
           <select v-model="permission" :class="selectClass" aria-label="Permission" :disabled="busy">
             <option v-for="p in PERMISSIONS" :key="p.value" :value="p.value">{{ p.label }}</option>
@@ -132,13 +164,13 @@ onMounted(load);
           <ul v-else class="flex flex-col gap-1">
             <li v-for="s in shares" :key="s.id" class="flex items-center gap-2 rounded-lg px-1 py-1">
               <div class="min-w-0 flex-1">
-                <p class="truncate text-sm text-neutral-800 dark:text-neutral-100">{{ s.member.display_name }}</p>
-                <p class="truncate text-xs text-neutral-400">{{ s.member.email }}</p>
+                <p class="truncate text-sm text-neutral-800 dark:text-neutral-100">{{ nameOf(s) }}</p>
+                <p class="truncate text-xs text-neutral-400">{{ detailOf(s) }}</p>
               </div>
               <select
                 :value="s.permission"
                 :class="selectClass"
-                :aria-label="`Permission for ${s.member.display_name}`"
+                :aria-label="`Permission for ${nameOf(s)}`"
                 :disabled="busy"
                 @change="change(s, ($event.target as HTMLSelectElement).value as SharePermission)"
               >
@@ -147,8 +179,8 @@ onMounted(load);
               <button
                 type="button"
                 class="icon-btn"
-                :title="`Stop sharing with ${s.member.display_name}`"
-                :aria-label="`Stop sharing with ${s.member.display_name}`"
+                :title="`Stop sharing with ${nameOf(s)}`"
+                :aria-label="`Stop sharing with ${nameOf(s)}`"
                 :disabled="busy"
                 @click="remove(s)"
               >
diff --git a/frontend/src/views/SettingsView.vue b/frontend/src/views/SettingsView.vue
index 46426ff..5bf82a0 100644
--- a/frontend/src/views/SettingsView.vue
+++ b/frontend/src/views/SettingsView.vue
@@ -5,6 +5,7 @@ import { useConfigStore } from "../stores/config";
 import BaseButton from "../components/BaseButton.vue";
 import InviteList from "../components/InviteList.vue";
 import AccountList from "../components/AccountList.vue";
+import GroupList from "../components/GroupList.vue";
 import { errorMessage } from "../api/errors";
 import { useUiStore } from "../stores/ui";
 
@@ -227,9 +228,10 @@ onMounted(load);
       </div>
     </form>
 
-    <!-- Outside the settings form: each invite and account action saves on its own,
+    <!-- Outside the settings form: each invite, account and group action saves on its own,
          and the form's Save button has nothing to do with them. -->
     <InviteList v-if="items.length" class="mt-10" />
     <AccountList v-if="items.length" class="mt-10" />
+    <GroupList v-if="items.length" class="mt-10" />
   </div>
 </template>