diff --git a/src/components/Composer/index.tsx b/src/components/Composer/index.tsx
index d93c7bb91a..d533d70f03 100644
--- a/src/components/Composer/index.tsx
+++ b/src/components/Composer/index.tsx
@@ -29,6 +29,7 @@ import {
   Autocomplete as AutocompleteBase,
   AutocompleteItemEmoji,
   AutocompleteItemProfile,
+  type LocalSource,
   parseAutocompleteItemType,
   useAutocomplete,
 } from '#/components/Autocomplete'
@@ -101,6 +102,8 @@ export type ComposerProps = Omit<
     undefined
   >['placement']
   disableEmojiFacets?: boolean
+  /** Local datasets weighted above remote results in the mention typeahead. */
+  localSources?: LocalSource[]
 }
 
 export function Composer({
@@ -117,6 +120,7 @@ export function Composer({
   autocompletePlacement,
   defaultValue,
   disableEmojiFacets = !IS_WEB,
+  localSources,
   ...rest
 }: ComposerProps) {
   const {theme: t, fonts} = useAlf()
@@ -377,6 +381,7 @@ export function Composer({
           inverted={autocompletePlacement?.startsWith('top')}
           sift={sift}
           activeFacet={activeFacet}
+          localSources={localSources}
           onDismiss={() => setActiveFacet(null)}
         />
       )}
@@ -392,16 +397,20 @@ function AutocompleteInner({
   inverted,
   sift,
   activeFacet,
+  localSources,
   onDismiss,
 }: {
   inverted?: boolean
   sift: UseSiftReturn
   activeFacet: TapperActiveFacet
+  localSources?: LocalSource[]
   onDismiss: () => void
 }) {
+  const itemType = parseAutocompleteItemType(activeFacet.type)
   const {items} = useAutocomplete({
-    type: parseAutocompleteItemType(activeFacet.type),
+    type: itemType,
     query: activeFacet.value,
+    sources: itemType === 'profile' ? localSources : undefined,
   })
 
   useEffect(() => {
diff --git a/src/features/autocomplete/useConvoMembersSource.ts b/src/features/autocomplete/useConvoMembersSource.ts
new file mode 100644
index 0000000000..567a21369c
--- /dev/null
+++ b/src/features/autocomplete/useConvoMembersSource.ts
@@ -0,0 +1,26 @@
+import {useConvo} from '#/state/messages/convo'
+import {useSession} from '#/state/session'
+import {type LocalSource} from '#/components/Autocomplete/types'
+
+/**
+ * Members of the active conversation as an autocomplete LocalSource, so the
+ * mention typeahead in a chat prioritizes the people in it. Must be used
+ * within a ConvoProvider.
+ */
+export function useConvoMembersSource(): LocalSource {
+  const convo = useConvo()
+  const {currentAccount} = useSession()
+  const members = convo.convo?.members ?? []
+
+  return {
+    key: 'convo-members',
+    items: members
+      .filter(member => member.did !== currentAccount?.did)
+      .map(member => ({
+        key: member.did,
+        type: 'profile' as const,
+        value: '@' + member.handle,
+        profile: member,
+      })),
+  }
+}
diff --git a/src/screens/Messages/components/MessageComposer.tsx b/src/screens/Messages/components/MessageComposer.tsx
index c5976fb688..5725716469 100644
--- a/src/screens/Messages/components/MessageComposer.tsx
+++ b/src/screens/Messages/components/MessageComposer.tsx
@@ -37,6 +37,8 @@ import {PaperPlaneVertical_Filled_Stroke2_Corner1_Rounded as PaperPlaneIcon} fro
 import {Loader} from '#/components/Loader'
 import * as Toast from '#/components/Toast'
 import {IS_ANDROID, IS_IOS, IS_LIQUID_GLASS, IS_NATIVE, IS_WEB} from '#/env'
+import {useConvoMembersSource} from '#/features/autocomplete/useConvoMembersSource'
+import {useFollowsSource} from '#/features/autocomplete/useFollowsSource'
 import {type MessageEmbedState} from './MessageInputEmbed'
 
 const MIN_HEIGHT = 40
@@ -71,6 +73,8 @@ export function MessageComposer({
 
   const [text, setText] = useState(getDraft)
   useSaveMessageDraft(text)
+  const convoMembers = useConvoMembersSource()
+  const follows = useFollowsSource()
 
   useEffect(() => {
     if (!replyTo) return
@@ -255,6 +259,7 @@ export function MessageComposer({
                     : l({message: 'Message', context: 'description'})
                 }
                 autocompletePlacement="top-start"
+                localSources={[convoMembers, follows]}
                 internalApiRef={composerInternalApiRef}
                 defaultValue={text}
                 editable={editable}