diff --git a/packages/schemas/alterations/next-1705991158-update-invitation-indices.ts b/packages/schemas/alterations/next-1705991158-update-invitation-indices.ts
new file mode 100644
index 000000000..9ec7e6eae
--- /dev/null
+++ b/packages/schemas/alterations/next-1705991158-update-invitation-indices.ts
@@ -0,0 +1,32 @@
+import { sql } from 'slonik';
+
+import type { AlterationScript } from '../lib/types/alteration.js';
+
+/**
+ * @fileoverview Separates the index (tenant_id, inviter_id, organization_id) to two indices. Also
+ * makes the inviter_id nullable.
+ */
+
+const alteration: AlterationScript = {
+  up: async (pool) => {
+    await pool.query(sql`
+      alter table organization_invitations
+        drop constraint organization_invitations_tenant_id_inviter_id_organization_fkey,
+        add foreign key (inviter_id) references users (id) on update cascade on delete cascade,
+        add foreign key (organization_id) references organizations (id) on update cascade on delete cascade,
+        alter column inviter_id drop not null;
+    `);
+  },
+  down: async (pool) => {
+    await pool.query(sql`
+      alter table organization_invitations
+        drop constraint organization_invitations_inviter_id_fkey,
+        drop constraint organization_invitations_organization_id_fkey,
+        add foreign key (tenant_id, inviter_id, organization_id) references organization_user_relations
+          (tenant_id, user_id, organization_id) on update cascade on delete cascade,
+        alter column inviter_id set not null;
+    `);
+  },
+};
+
+export default alteration;
diff --git a/packages/schemas/tables/organization_invitations.sql b/packages/schemas/tables/organization_invitations.sql
index 7f71af829..fb3d2af95 100644
--- a/packages/schemas/tables/organization_invitations.sql
+++ b/packages/schemas/tables/organization_invitations.sql
@@ -9,14 +9,16 @@ create table organization_invitations (
   /** The unique identifier of the invitation. */
   id varchar(21) not null,
   /** The user ID who sent the invitation. */
-  inviter_id varchar(21) not null,
+  inviter_id varchar(21)
+    references users (id) on update cascade on delete cascade,
   /** The email address or other identifier of the invitee. */
   invitee varchar(256) not null,
   /** The user ID of who accepted the invitation. */
   accepted_user_id varchar(21)
     references users (id) on update cascade on delete cascade,
   /** The ID of the organization to which the invitee is invited. */
-  organization_id varchar(21) not null,
+  organization_id varchar(21) not null
+    references organizations (id) on update cascade on delete cascade,
   /** The status of the invitation. */
   status organization_invitation_status not null,
   /** The ID of the magic link that can be used to accept the invitation. */
@@ -28,10 +30,7 @@ create table organization_invitations (
   updated_at timestamptz not null default (now()),
   /** The time when the invitation expires. */
   expires_at timestamptz not null,
-  primary key (id),
-  foreign key (tenant_id, inviter_id, organization_id)
-    references organization_user_relations (tenant_id, user_id, organization_id)
-    on update cascade on delete cascade
+  primary key (id)
 );
 
 -- Ensure there is only one pending invitation for a given invitee and organization.