diff --git a/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests.csproj b/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests.csproj
index ff49c62..817ef72 100644
--- a/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests.csproj
+++ b/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests/TomLonghurst.ReadableTimeSpan.Newtonsoft.Json.UnitTests.csproj
@@ -9,7 +9,7 @@
 
     <ItemGroup>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.1" />
-        <PackageReference Include="NUnit" Version="4.6.1" />
+        <PackageReference Include="NUnit" Version="5.0.0" />
         <PackageReference Include="NUnit3TestAdapter" Version="6.3.0" />
         <PackageReference Include="coverlet.collector" Version="10.0.1" />
     </ItemGroup>
diff --git a/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests.csproj b/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests.csproj
index 65cbb3c..c2f0039 100644
--- a/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests.csproj
+++ b/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests/TomLonghurst.ReadableTimeSpan.System.Text.Json.UnitTests.csproj
@@ -9,7 +9,7 @@
 
     <ItemGroup>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.1" />
-        <PackageReference Include="NUnit" Version="4.6.1" />
+        <PackageReference Include="NUnit" Version="5.0.0" />
         <PackageReference Include="NUnit3TestAdapter" Version="6.3.0" />
         <PackageReference Include="coverlet.collector" Version="10.0.1" />
     </ItemGroup>
diff --git a/TomLonghurst.ReadableTimeSpan.UnitTests/TomLonghurst.ReadableTimeSpan.UnitTests.csproj b/TomLonghurst.ReadableTimeSpan.UnitTests/TomLonghurst.ReadableTimeSpan.UnitTests.csproj
index c9b1b38..71ff183 100644
--- a/TomLonghurst.ReadableTimeSpan.UnitTests/TomLonghurst.ReadableTimeSpan.UnitTests.csproj
+++ b/TomLonghurst.ReadableTimeSpan.UnitTests/TomLonghurst.ReadableTimeSpan.UnitTests.csproj
@@ -12,7 +12,7 @@
         <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="10.0.12" />
         <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="10.0.12" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.1" />
-        <PackageReference Include="NUnit" Version="4.6.1" />
+        <PackageReference Include="NUnit" Version="5.0.0" />
         <PackageReference Include="NUnit3TestAdapter" Version="6.3.0" />
         <PackageReference Include="coverlet.collector" Version="10.0.1" />
     </ItemGroup>