diff --git a/data/test.schema.json b/data/test.schema.json
index e87e7d03a9e5..1fe60a694c14 100644
--- a/data/test.schema.json
+++ b/data/test.schema.json
@@ -43,7 +43,9 @@
               "msvc",
               "gcc",
               "cygwin",
-              "!cygwin"
+              "!cygwin",
+              "windows",
+              "!windows"
             ]
           },
           "version": {
diff --git a/docs/markdown/Contributing.md b/docs/markdown/Contributing.md
index 8f796ab65530..72ed7dbbd323 100644
--- a/docs/markdown/Contributing.md
+++ b/docs/markdown/Contributing.md
@@ -320,6 +320,8 @@ considered if the platform matches. The following values for
 | `gcc`      | Not `msvc`                                                           |
 | `cygwin`   | Matches when the platform is cygwin                                  |
 | `!cygwin`  | Not `cygwin`                                                         |
+| `windows`  | Matches when the platform is windows or cygwin                       |
+| `!windows` | Not `windows`                                                        |
 
 #### matrix
 
diff --git a/run_project_tests.py b/run_project_tests.py
index ab34c27f21d2..79d35c8fc4b0 100755
--- a/run_project_tests.py
+++ b/run_project_tests.py
@@ -158,6 +158,8 @@ def get_path(self, compiler: str, env: environment.Environment) -> T.Optional[Pa
             'gcc': canonical_compiler != 'msvc',
             'cygwin': env.machines.host.is_cygwin(),
             '!cygwin': not env.machines.host.is_cygwin(),
+            'windows': env.machines.host.is_windows() or env.machines.host.is_cygwin(),
+            '!windows': not env.machines.host.is_windows() or env.machines.host.is_cygwin(),
         }.get(self.platform or '', True)
         if not matches:
             return None
diff --git a/test cases/common/230 external project/test.json b/test cases/common/230 external project/test.json
index 4df7d4ac57ff..ff8b55838647 100644
--- a/test cases/common/230 external project/test.json	
+++ b/test cases/common/230 external project/test.json	
@@ -1,7 +1,7 @@
 {
   "installed": [
-    { "type": "shared_lib",  "file": "usr/lib/foo", "platform": "!cygwin" },
-    { "type": "file",  "file": "usr/lib/libfoo.dll", "platform": "cygwin" },
+    { "type": "shared_lib",  "file": "usr/lib/foo", "platform": "!windows" },
+    { "type": "file",  "file": "usr/lib/libfoo.dll", "platform": "windows" },
     { "type": "file",  "file": "usr/include/libfoo.h" },
     { "type": "file", "file": "usr/lib/pkgconfig/somelib.pc" }
   ]