diff --git a/lib/shared/reaction-utils.js b/lib/shared/reaction-utils.js
--- a/lib/shared/reaction-utils.js
+++ b/lib/shared/reaction-utils.js
@@ -2,7 +2,9 @@
 
 import invariant from 'invariant';
 import _sortBy from 'lodash/fp/sortBy';
+import * as React from 'react';
 
+import { useENSNames } from '../hooks/ens-cache';
 import type { MessageReactionInfo } from '../selectors/chat-selectors';
 import type {
   RobotextMessageInfo,
@@ -41,31 +43,34 @@
   +username: string,
 };
 
-function createMessageReactionsList(
+function useMessageReactionsList(
   reactions: $ReadOnlyMap<string, MessageReactionInfo>,
 ): $ReadOnlyArray<MessageReactionListInfo> {
-  const result = [];
-
-  for (const [reaction, reactionInfo] of reactions) {
-    reactionInfo.users.forEach(user => {
-      result.push({
-        ...user,
-        username: stringForUserExplicit(user),
-        reaction,
+  const withoutENSNames = React.useMemo(() => {
+    const result = [];
+
+    for (const [reaction, reactionInfo] of reactions) {
+      reactionInfo.users.forEach(user => {
+        result.push({
+          ...user,
+          username: stringForUserExplicit(user),
+          reaction,
+        });
       });
-    });
-  }
-
-  const sortByNumReactions = (reactionInfo: MessageReactionListInfo) => {
-    const numOfReactions = reactions.get(reactionInfo.reaction)?.users.length;
-    return numOfReactions ? -numOfReactions : 0;
-  };
+    }
 
-  return _sortBy(
-    ([sortByNumReactions, 'username']: $ReadOnlyArray<
-      ((reactionInfo: MessageReactionListInfo) => mixed) | string,
-    >),
-  )(result);
+    const sortByNumReactions = (reactionInfo: MessageReactionListInfo) => {
+      const numOfReactions = reactions.get(reactionInfo.reaction)?.users.length;
+      return numOfReactions ? -numOfReactions : 0;
+    };
+
+    return _sortBy(
+      ([sortByNumReactions, 'username']: $ReadOnlyArray<
+        ((reactionInfo: MessageReactionListInfo) => mixed) | string,
+      >),
+    )(result);
+  }, [reactions]);
+  return useENSNames<MessageReactionListInfo>(withoutENSNames);
 }
 
 function useCanCreateReactionFromMessage(
@@ -99,6 +104,6 @@
 
 export {
   stringForReactionList,
-  createMessageReactionsList,
+  useMessageReactionsList,
   useCanCreateReactionFromMessage,
 };
diff --git a/native/chat/message-reactions-modal.react.js b/native/chat/message-reactions-modal.react.js
--- a/native/chat/message-reactions-modal.react.js
+++ b/native/chat/message-reactions-modal.react.js
@@ -6,7 +6,7 @@
 import { View, Text, FlatList, TouchableHighlight } from 'react-native';
 
 import type { MessageReactionInfo } from 'lib/selectors/chat-selectors';
-import { createMessageReactionsList } from 'lib/shared/reaction-utils';
+import { useMessageReactionsList } from 'lib/shared/reaction-utils';
 
 import Modal from '../components/modal.react';
 import type { RootNavigationProp } from '../navigation/root-navigator.react';
@@ -32,10 +32,7 @@
 
   const close = React.useCallback(() => navigation.goBack(), [navigation]);
 
-  const reactionsListData = React.useMemo(
-    () => createMessageReactionsList(reactions),
-    [reactions],
-  );
+  const reactionsListData = useMessageReactionsList(reactions);
 
   const renderItem = React.useCallback(
     ({ item }) => {
diff --git a/web/modals/chat/message-reactions-modal.react.js b/web/modals/chat/message-reactions-modal.react.js
--- a/web/modals/chat/message-reactions-modal.react.js
+++ b/web/modals/chat/message-reactions-modal.react.js
@@ -3,7 +3,7 @@
 import * as React from 'react';
 
 import type { MessageReactionInfo } from 'lib/selectors/chat-selectors';
-import { createMessageReactionsList } from 'lib/shared/reaction-utils';
+import { useMessageReactionsList } from 'lib/shared/reaction-utils';
 
 import Modal from '../modal.react';
 import css from './message-reactions-modal.css';
@@ -16,16 +16,18 @@
 function MessageReactionsModal(props: Props): React.Node {
   const { onClose, reactions } = props;
 
-  const reactionsList = React.useMemo(() => {
-    const messageReactionsList = createMessageReactionsList(reactions);
-
-    return messageReactionsList.map(messageReactionUser => (
-      <div key={messageReactionUser.id} className={css.userRowContainer}>
-        <div>{messageReactionUser.username}</div>
-        <div>{messageReactionUser.reaction}</div>
-      </div>
-    ));
-  }, [reactions]);
+  const messageReactionsList = useMessageReactionsList(reactions);
+
+  const reactionsList = React.useMemo(
+    () =>
+      messageReactionsList.map(messageReactionUser => (
+        <div key={messageReactionUser.id} className={css.userRowContainer}>
+          <div>{messageReactionUser.username}</div>
+          <div>{messageReactionUser.reaction}</div>
+        </div>
+      )),
+    [messageReactionsList],
+  );
 
   return (
     <Modal size="large" name="Reactions" onClose={onClose}>