diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 795d1845f6..27b1aa42ba 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -339,6 +339,13 @@ Example:
 for
 ```
 
+#### Tests covering code which has OS-specific behaviour
+
+Most code in PHP_CodeSniffer is operating system agnostic.
+However, there are a few places which include OS-specific conditions, most notably for Windows.
+
+Tests which cover code which have Windows specific conditions should be marked with a `@group Windows` annotation to allow for running those tests separately/selectively in CI.
+
 
 ### Submitting Your Pull Request
 
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6645cb7f7f..0113b7e8a7 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -92,6 +92,11 @@ jobs:
         php: ['5.4', '5.5', '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5']
         custom_ini: [false]
 
+        exclude:
+          # Installing on Windows with PHP 5.4 runs into all sorts of problems (which are not ours).
+          - php: '5.4'
+            os: 'windows-latest'
+
         include:
           # Skip test runs on builds which are also run in the coverage job.
           # Note: the tests on PHP 7.2 will still be run as the coverage build uses custom_ini settings for that version.
diff --git a/src/Standards/Generic/Tests/Debug/CSSLintUnitTest.php b/src/Standards/Generic/Tests/Debug/CSSLintUnitTest.php
index 83f875cb0f..e4afa67b63 100644
--- a/src/Standards/Generic/Tests/Debug/CSSLintUnitTest.php
+++ b/src/Standards/Generic/Tests/Debug/CSSLintUnitTest.php
@@ -16,6 +16,8 @@
  * Unit test class for the CSSLint sniff.
  *
  * @covers \PHP_CodeSniffer\Standards\Generic\Sniffs\Debug\CSSLintSniff
+ * @covers \PHP_CodeSniffer\Config::getExecutablePath
+ * @group  Windows
  */
 final class CSSLintUnitTest extends AbstractSniffUnitTest
 {
diff --git a/tests/Core/Fixer/GenerateDiffTest.php b/tests/Core/Fixer/GenerateDiffTest.php
index 9b3f115e40..b7902bbe61 100644
--- a/tests/Core/Fixer/GenerateDiffTest.php
+++ b/tests/Core/Fixer/GenerateDiffTest.php
@@ -21,6 +21,7 @@
  * test running the fixer itself, nor generating a diff based on a fixer run.
  *
  * @covers PHP_CodeSniffer\Fixer::generateDiff
+ * @group  Windows
  */
 final class GenerateDiffTest extends TestCase
 {