diff --git a/test/Infrastructure.IntegrationTest/AdminConsole/Repositories/CollectionRepository/DefaultCollectionSemaphoreTests.cs b/test/Infrastructure.IntegrationTest/AdminConsole/Repositories/CollectionRepository/DefaultCollectionSemaphoreTests.cs
new file mode 100644
index 0000000000..38dd28b367
--- /dev/null
+++ b/test/Infrastructure.IntegrationTest/AdminConsole/Repositories/CollectionRepository/DefaultCollectionSemaphoreTests.cs
@@ -0,0 +1,78 @@
+using Bit.Core.AdminConsole.Entities;
+using Bit.Core.Billing.Enums;
+using Bit.Core.Entities;
+using Bit.Core.Enums;
+using Bit.Core.Repositories;
+using Bit.Infrastructure.EntityFramework.Repositories;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+
+namespace Bit.Infrastructure.IntegrationTest.AdminConsole.Repositories.CollectionRepository;
+
+/// <summary>
+/// Tests for DefaultCollectionSemaphore table behavior including cascade deletions
+/// </summary>
+public class DefaultCollectionSemaphoreTests
+{
+    [Theory, DatabaseData]
+    public async Task DeleteOrganizationUser_CascadeDeletesSemaphore(
+        IUserRepository userRepository,
+        IOrganizationRepository organizationRepository,
+        ICollectionRepository collectionRepository,
+        IOrganizationUserRepository organizationUserRepository)
+    {
+        // Arrange
+        var user = await userRepository.CreateTestUserAsync();
+        var organization = await organizationRepository.CreateTestOrganizationAsync();
+        var orgUser = await organizationUserRepository.CreateTestOrganizationUserAsync(organization, user);
+
+        await collectionRepository.UpsertDefaultCollectionsAsync(
+            organization.Id,
+            [orgUser.Id],
+            "My Items");
+
+        // Verify semaphore exists
+        var semaphoreBefore = await collectionRepository.GetDefaultCollectionSemaphoresAsync(organization.Id);
+        Assert.Single(semaphoreBefore, s => s == orgUser.Id);
+
+        // Act - Delete organization user
+        await organizationUserRepository.DeleteAsync(orgUser);
+
+        // Assert - Semaphore should be cascade deleted
+        var semaphoreAfter = await collectionRepository.GetDefaultCollectionSemaphoresAsync(organization.Id);
+        Assert.Empty(semaphoreAfter);
+    }
+
+    /// <summary>
+    /// Test that deleting an Organization cascades through OrganizationUser to DefaultCollectionSemaphore
+    /// Note: Cascade path is Organization -> OrganizationUser -> DefaultCollectionSemaphore (not direct)
+    /// </summary>
+    [Theory, DatabaseData]
+    public async Task DeleteOrganization_CascadeDeletesSemaphore_ThroughOrganizationUser(
+        IUserRepository userRepository,
+        IOrganizationRepository organizationRepository,
+        ICollectionRepository collectionRepository,
+        IOrganizationUserRepository organizationUserRepository)
+    {
+        // Arrange
+        var user = await userRepository.CreateTestUserAsync();
+        var organization = await organizationRepository.CreateTestOrganizationAsync();
+        var orgUser = await organizationUserRepository.CreateTestOrganizationUserAsync(organization, user);
+
+        await collectionRepository.UpsertDefaultCollectionsAsync(
+            organization.Id,
+            [orgUser.Id],
+            "My Items");
+
+        // Verify semaphore exists
+        var semaphoreBefore = await collectionRepository.GetDefaultCollectionSemaphoresAsync(organization.Id);
+        Assert.Single(semaphoreBefore, s => s == orgUser.Id);
+
+        // Act - Delete organization (which cascades to OrganizationUser, which cascades to semaphore)
+        await organizationRepository.DeleteAsync(organization);
+
+        // Assert - Semaphore should be cascade deleted via OrganizationUser
+        var semaphoreAfter = await collectionRepository.GetDefaultCollectionSemaphoresAsync(organization.Id);
+        Assert.Empty(semaphoreAfter);
+    }
+}