diff --git a/services/domain/Big.Application/BeoordeelRegistratie.cs b/services/domain/Big.Application/BeoordeelRegistratie.cs
index f0a384f..8ba8e3f 100644
--- a/services/domain/Big.Application/BeoordeelRegistratie.cs
+++ b/services/domain/Big.Application/BeoordeelRegistratie.cs
@@ -20,10 +20,12 @@ public sealed record BeoordeelRegistratieCommand(RegistrationId RegistrationId,
 /// <see cref="BeoordelingsBesluit.Goedkeuren"/> sets the zaak's final status via the ACL (§8.1) and
 /// advances the aggregate to INGESCHREVEN; <see cref="BeoordelingsBesluit.Afwijzen"/> advances it to
 /// AFGEWEZEN in the domain (propagating a rejection to the zaak, so the openbaar projection reflects
-/// it, is a later sub-slice of S-12). Both decisions are idempotent — a repeated or redelivered
-/// decision that matches the current terminal state is a no-op, so the ACL is not called twice.
+/// it, is a later sub-slice of S-12). After applying the decision it completes the Flowable
+/// <c>Beoordelen</c> task (found by registrationId) so the workflow advances (ADR-0013). Both
+/// decisions are idempotent — a repeated or redelivered decision that matches the current terminal
+/// state is a no-op, so the ACL is not called and the task not completed twice.
 /// </summary>
-public sealed class BeoordeelRegistratie(IRegistrationStore store, IAclClient acl)
+public sealed class BeoordeelRegistratie(IRegistrationStore store, IAclClient acl, IUserTaskClient tasks)
 {
     public async Task HandleAsync(BeoordeelRegistratieCommand command, CancellationToken ct = default)
     {
@@ -53,5 +55,17 @@ public sealed class BeoordeelRegistratie(IRegistrationStore store, IAclClient ac
         }
 
         await store.SaveAsync(registration, ct);
+        await CompleteWorkflowTaskAsync(command.RegistrationId, command.Besluit, ct);
+    }
+
+    // Advance the workflow: complete the open Beoordelen task for this registration. If none is open
+    // (already completed, or the process hasn't parked yet) the decision still stands — we complete
+    // nothing rather than fail.
+    private async Task CompleteWorkflowTaskAsync(RegistrationId registrationId, BeoordelingsBesluit besluit, CancellationToken ct)
+    {
+        var open = await tasks.GetOpenBeoordelingenAsync(ct);
+        var task = open.FirstOrDefault(t => t.RegistrationId == registrationId);
+        if (task is not null)
+            await tasks.CompleteBeoordelingAsync(task.TaskId, besluit, ct);
     }
 }