diff --git a/lib/shared/avatar-utils.js b/lib/shared/avatar-utils.js
--- a/lib/shared/avatar-utils.js
+++ b/lib/shared/avatar-utils.js
@@ -1,9 +1,17 @@
 // @flow
 
+import invariant from 'invariant';
 import stringHash from 'string-hash';
 
 import { selectedThreadColors } from './color-utils.js';
+import { threadOtherMembers } from './thread-utils.js';
 import type { ClientEmojiAvatar, ClientAvatar } from '../types/avatar-types.js';
+import {
+  type RawThreadInfo,
+  type ThreadInfo,
+  threadTypes,
+} from '../types/thread-types.js';
+import type { UserInfos } from '../types/user-types.js';
 
 const defaultAnonymousUserEmojiAvatar: ClientEmojiAvatar = {
   color: selectedThreadColors[4],
@@ -57,4 +65,30 @@
   return getDefaultAvatar(user.username);
 }
 
-export { getAvatarForUser };
+function getUserAvatarForThread(
+  threadInfo: RawThreadInfo | ThreadInfo,
+  viewerID: ?string,
+  userInfos: UserInfos,
+): ClientAvatar {
+  if (threadInfo.type === threadTypes.PRIVATE) {
+    invariant(viewerID, 'viewerID should be set for PRIVATE threads');
+    return getAvatarForUser(userInfos[viewerID]);
+  }
+
+  invariant(
+    threadInfo.type === threadTypes.PERSONAL,
+    'threadInfo should be a PERSONAL type',
+  );
+
+  const memberInfos = threadOtherMembers(threadInfo.members, viewerID)
+    .map(member => userInfos[member.id] && userInfos[member.id])
+    .filter(Boolean);
+
+  if (memberInfos.length === 0) {
+    return defaultAnonymousUserEmojiAvatar;
+  }
+
+  return getAvatarForUser(memberInfos[0]);
+}
+
+export { getAvatarForUser, getUserAvatarForThread };
diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -41,6 +41,7 @@
   getRelativeMemberInfos,
   usersWithPersonalThreadSelector,
 } from '../selectors/user-selectors.js';
+import { getUserAvatarForThread } from '../shared/avatar-utils.js';
 import type { CalendarQuery } from '../types/entry-types.js';
 import {
   type RobotextMessageInfo,
@@ -867,10 +868,22 @@
     ...threadInfo,
     uiName: threadUIName(threadInfo),
   };
-  const { sourceMessageID } = rawThreadInfo;
+  const { sourceMessageID, avatar } = rawThreadInfo;
   if (sourceMessageID) {
     threadInfo = { ...threadInfo, sourceMessageID };
   }
+
+  if (avatar) {
+    threadInfo = { ...threadInfo, avatar };
+  } else if (
+    rawThreadInfo.type === threadTypes.PERSONAL ||
+    rawThreadInfo.type === threadTypes.PRIVATE
+  ) {
+    threadInfo = {
+      ...threadInfo,
+      avatar: getUserAvatarForThread(rawThreadInfo, viewerID, userInfos),
+    };
+  }
   return threadInfo;
 }
 
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -2,6 +2,7 @@
 
 import invariant from 'invariant';
 
+import type { ClientAvatar } from './avatar-types.js';
 import type { Shape } from './core.js';
 import type { CalendarQuery, RawEntryInfo } from './entry-types.js';
 import type { Media } from './media-types.js';
@@ -194,6 +195,7 @@
   +id: string,
   +type: ThreadType,
   +name: ?string,
+  +avatar?: ?ClientAvatar,
   +description: ?string,
   +color: string, // hex, without "#" or "0x"
   +creationTime: number, // millisecond timestamp
@@ -212,6 +214,7 @@
   +type: ThreadType,
   +name: ?string,
   +uiName: string | ThreadEntity,
+  +avatar?: ?ClientAvatar,
   +description: ?string,
   +color: string, // hex, without "#" or "0x"
   +creationTime: number, // millisecond timestamp
@@ -230,6 +233,7 @@
   +type: ThreadType,
   +name: ?string,
   +uiName: string,
+  +avatar?: ?ClientAvatar,
   +description: ?string,
   +color: string, // hex, without "#" or "0x"
   +creationTime: number, // millisecond timestamp
@@ -296,6 +300,7 @@
   +id: string,
   +type: number,
   +name: ?string,
+  +avatar?: ?ClientAvatar,
   +description: ?string,
   +color: string,
   +creationTime: string,