diff --git a/treeherder/model/migrations/0046_repository_repo_url_active_idx.py b/treeherder/model/migrations/0046_repository_repo_url_active_idx.py
new file mode 100644
index 00000000000..a6be0b6efa8
--- /dev/null
+++ b/treeherder/model/migrations/0046_repository_repo_url_active_idx.py
@@ -0,0 +1,27 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    # Use non-atomic so we can create the index CONCURRENTLY
+    atomic = False
+
+    dependencies = [
+        ("model", "0045_alter_failureline_expected_alter_failureline_level_and_more"),
+    ]
+
+    operations = [
+        migrations.SeparateDatabaseAndState(
+            database_operations=[
+                migrations.RunSQL(
+                    sql="CREATE INDEX CONCURRENTLY IF NOT EXISTS repo_url_active_idx ON repository (url, active_status);",
+                    reverse_sql="DROP INDEX IF EXISTS repo_url_active_idx;",
+                ),
+            ],
+            state_operations=[
+                migrations.AddIndex(
+                    model_name="repository",
+                    index=models.Index(fields=["url", "active_status"], name="repo_url_active_idx"),
+                ),
+            ],
+        ),
+    ]
diff --git a/treeherder/model/models.py b/treeherder/model/models.py
index 6de26f11329..eb9386d0f2b 100644
--- a/treeherder/model/models.py
+++ b/treeherder/model/models.py
@@ -113,6 +113,9 @@ class Repository(models.Model):
     class Meta:
         db_table = "repository"
         verbose_name_plural = "repositories"
+        indexes = [
+            models.Index(fields=["url", "active_status"], name="repo_url_active_idx"),
+        ]
 
     @classmethod
     def fetch_all_names(cls) -> list[str]: