diff --git a/src/NServiceBus.TransactionalSession.AcceptanceTests/NServiceBus.TransactionalSession.AcceptanceTests.csproj b/src/NServiceBus.TransactionalSession.AcceptanceTests/NServiceBus.TransactionalSession.AcceptanceTests.csproj
index 385310f..fe162a5 100644
--- a/src/NServiceBus.TransactionalSession.AcceptanceTests/NServiceBus.TransactionalSession.AcceptanceTests.csproj
+++ b/src/NServiceBus.TransactionalSession.AcceptanceTests/NServiceBus.TransactionalSession.AcceptanceTests.csproj
@@ -14,7 +14,7 @@
   <ItemGroup>
     <PackageReference Include="GitHubActionsTestLogger" Version="2.3.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.0.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
     <PackageReference Include="NServiceBus.AcceptanceTesting" Version="9.0.0-alpha.9" />
   </ItemGroup>
diff --git a/src/NServiceBus.TransactionalSession.Tests/NServiceBus.TransactionalSession.Tests.csproj b/src/NServiceBus.TransactionalSession.Tests/NServiceBus.TransactionalSession.Tests.csproj
index 1d65f50..b038ded 100644
--- a/src/NServiceBus.TransactionalSession.Tests/NServiceBus.TransactionalSession.Tests.csproj
+++ b/src/NServiceBus.TransactionalSession.Tests/NServiceBus.TransactionalSession.Tests.csproj
@@ -13,7 +13,7 @@
   <ItemGroup>
     <PackageReference Include="GitHubActionsTestLogger" Version="2.3.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit" Version="4.0.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
   </ItemGroup>