diff --git a/crates/storage-pg/migrations/20251023134634_personal_access_tokens_unique_fix.sql b/crates/storage-pg/migrations/20251023134634_personal_access_tokens_unique_fix.sql
new file mode 100644
index 000000000..9274d16ac
--- /dev/null
+++ b/crates/storage-pg/migrations/20251023134634_personal_access_tokens_unique_fix.sql
@@ -0,0 +1,14 @@
+-- Copyright 2025 Element Creations Ltd.
+--
+-- SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+-- Please see LICENSE in the repository root for full details.
+
+
+-- Fix a faulty constraint.
+-- The condition was incorrectly specified as `revoked_at IS NOT NULL`
+-- when `revoked_at IS NULL` was meant.
+
+DROP INDEX personal_access_tokens_personal_session_id_idx;
+
+-- Ensure we can only have one active personal access token in each family.
+CREATE UNIQUE INDEX ON personal_access_tokens (personal_session_id) WHERE revoked_at IS NULL;
diff --git a/crates/storage-pg/src/personal/mod.rs b/crates/storage-pg/src/personal/mod.rs
index aa4597fec..f540a6be3 100644
--- a/crates/storage-pg/src/personal/mod.rs
+++ b/crates/storage-pg/src/personal/mod.rs
@@ -384,6 +384,11 @@ mod tests {
         assert!(!token.is_valid(clock.now()));
 
         // Add a second access token, this time without expiration
+        let _token = repo
+            .personal_access_token()
+            .revoke(&clock, token)
+            .await
+            .unwrap();
         let token = repo
             .personal_access_token()
             .add(&mut rng, &clock, &session, SECOND_TOKEN, None)