diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 9bde77235a..0a691a872e 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -8079,6 +8079,7 @@ XML:
   - ".scxml"
   - ".sfproj"
   - ".shproj"
+  - ".slnx"
   - ".srdf"
   - ".storyboard"
   - ".sublime-snippet"
diff --git a/samples/XML/Robots.slnx b/samples/XML/Robots.slnx
new file mode 100644
index 0000000000..a56dadf61d
--- /dev/null
+++ b/samples/XML/Robots.slnx
@@ -0,0 +1,10 @@
+<Solution>
+  <Project Path="build\Robots.Build\Robots.Build.csproj" />
+  <Project Path="src\Robots.Grasshopper\Robots.Grasshopper.csproj">
+    <BuildDependency Project="src\Robots\Robots.csproj" />
+  </Project>
+  <Project Path="src\Robots\Robots.csproj" />
+  <Project Path="tests\Robots.Tests\Robots.Tests.csproj">
+    <BuildDependency Project="src\Robots\Robots.csproj" />
+  </Project>
+</Solution>
diff --git a/test/test_strategies.rb b/test/test_strategies.rb
index b57ae907e6..b5640bee6b 100644
--- a/test/test_strategies.rb
+++ b/test/test_strategies.rb
@@ -189,7 +189,8 @@ def test_xml
       "#{samples_path}/XML/some-ideas.mm",
       "#{samples_path}/XML/GMOculus.project.gmx",
       "#{samples_path}/XML/obj_control.object.gmx",
-      "#{samples_path}/XML/MainView.axaml"
+      "#{samples_path}/XML/MainView.axaml",
+      "#{samples_path}/XML/Robots.slnx",
     ]
     assert_all_xml all_xml_fixtures("*") - no_root_tag