diff --git a/dist/setup/index.js b/dist/setup/index.js
index d3bf3ead..b06b72ea 100644
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@@ -91118,7 +91118,12 @@ function useCpythonVersion(version, architecture, updateEnvironment, checkLatest
             // On Linux and macOS, pip will create the --user directory and add it to PATH as needed.
         }
         const installed = versionFromPath(installDir);
-        core.setOutput('python-version', installed);
+        let pythonVersion = installed;
+        if (freethreaded) {
+            // Add the freethreaded suffix to the version (e.g., 3.13.1t)
+            pythonVersion += 't';
+        }
+        core.setOutput('python-version', pythonVersion);
         core.setOutput('python-path', pythonPath);
         return { impl: 'CPython', version: installed };
     });
diff --git a/src/find-python.ts b/src/find-python.ts
index 606c4802..1cf47fa4 100644
--- a/src/find-python.ts
+++ b/src/find-python.ts
@@ -165,7 +165,12 @@ export async function useCpythonVersion(
   }
 
   const installed = versionFromPath(installDir);
-  core.setOutput('python-version', installed);
+  let pythonVersion = installed;
+  if (freethreaded) {
+    // Add the freethreaded suffix to the version (e.g., 3.13.1t)
+    pythonVersion += 't';
+  }
+  core.setOutput('python-version', pythonVersion);
   core.setOutput('python-path', pythonPath);
 
   return {impl: 'CPython', version: installed};