diff --git a/ModelBuilder.UnitTests/ModelBuilder.UnitTests.csproj b/ModelBuilder.UnitTests/ModelBuilder.UnitTests.csproj
index 25881cb..95f5cde 100644
--- a/ModelBuilder.UnitTests/ModelBuilder.UnitTests.csproj
+++ b/ModelBuilder.UnitTests/ModelBuilder.UnitTests.csproj
@@ -17,7 +17,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="NodaTime" Version="3.1.11" />
-    <PackageReference Include="nsubstitute" Version="5.1.0" />
+    <PackageReference Include="nsubstitute" Version="5.3.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
     <PackageReference Include="xunit" Version="2.9.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">