diff --git a/apps/api/migrations/000014_module_join_indexes.down.sql b/apps/api/migrations/000014_module_join_indexes.down.sql
new file mode 100644
index 0000000..dfbde6b
--- /dev/null
+++ b/apps/api/migrations/000014_module_join_indexes.down.sql
@@ -0,0 +1,4 @@
+DROP INDEX IF EXISTS idx_module_issues_module;
+DROP INDEX IF EXISTS idx_module_issues_issue;
+DROP INDEX IF EXISTS idx_module_members_module;
+DROP INDEX IF EXISTS idx_module_links_module;
diff --git a/apps/api/migrations/000014_module_join_indexes.up.sql b/apps/api/migrations/000014_module_join_indexes.up.sql
new file mode 100644
index 0000000..2ae32a8
--- /dev/null
+++ b/apps/api/migrations/000014_module_join_indexes.up.sql
@@ -0,0 +1,8 @@
+-- The module join tables had no indexes, so every lookup by module_id or
+-- issue_id did a sequential scan (ListModuleIssueIDs, RemoveModuleIssue,
+-- CountIssuesByModuleIDs, ListMemberIDsByModuleIDs, the progress join, etc.).
+-- The cycle join tables already have the equivalent indexes; add them here.
+CREATE INDEX IF NOT EXISTS idx_module_issues_module ON module_issues (module_id);
+CREATE INDEX IF NOT EXISTS idx_module_issues_issue ON module_issues (issue_id);
+CREATE INDEX IF NOT EXISTS idx_module_members_module ON module_members (module_id);
+CREATE INDEX IF NOT EXISTS idx_module_links_module ON module_links (module_id);