diff --git a/app/javascript/mastodon/api_types/polls.ts b/app/javascript/mastodon/api_types/polls.ts
index 891a2faba79..1ff2a6a5cba 100644
--- a/app/javascript/mastodon/api_types/polls.ts
+++ b/app/javascript/mastodon/api_types/polls.ts
@@ -9,7 +9,7 @@ export interface ApiPollOptionJSON {
 
 export interface ApiPollJSON {
   id: string;
-  expires_at: string;
+  expires_at: string | null;
   expired: boolean;
   multiple: boolean;
   votes_count: number;
diff --git a/app/javascript/mastodon/components/poll.tsx b/app/javascript/mastodon/components/poll.tsx
index 98954fc2d95..472485a02cd 100644
--- a/app/javascript/mastodon/components/poll.tsx
+++ b/app/javascript/mastodon/components/poll.tsx
@@ -59,10 +59,13 @@ export const Poll: React.FC<PollProps> = ({ pollId, disabled, status }) => {
       return false;
     }
     const expiresAt = poll.expires_at;
-    return poll.expired || new Date(expiresAt).getTime() < Date.now();
+    return (
+      poll.expired ||
+      (expiresAt !== null && new Date(expiresAt).getTime() < Date.now())
+    );
   }, [poll]);
   const timeRemaining = useMemo(() => {
-    if (!poll) {
+    if (!poll?.expires_at) {
       return null;
     }
     if (expired) {