diff --git a/dist/setup/index.js b/dist/setup/index.js
index 4afa92b..3298e22 100644
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@@ -6112,6 +6112,9 @@ function run() {
                     yield cacheDependencies(cache, pythonVersion);
                 }
             }
+            else {
+                core.warning('The `python-version` input is not set.  The version of Python currently in `PATH` will be used.');
+            }
             const matchersPath = path.join(__dirname, '../..', '.github');
             core.info(`##[add-matcher]${path.join(matchersPath, 'python.json')}`);
         }
diff --git a/src/setup-python.ts b/src/setup-python.ts
index 37229c5..82a9207 100644
--- a/src/setup-python.ts
+++ b/src/setup-python.ts
@@ -53,6 +53,10 @@ async function run() {
       if (cache && isCacheFeatureAvailable()) {
         await cacheDependencies(cache, pythonVersion);
       }
+    } else {
+      core.warning(
+        'The `python-version` input is not set.  The version of Python currently in `PATH` will be used.'
+      );
     }
     const matchersPath = path.join(__dirname, '../..', '.github');
     core.info(`##[add-matcher]${path.join(matchersPath, 'python.json')}`);