diff --git a/libc/include/android/api-level.h b/libc/include/android/api-level.h
index 1b8af78..50cb61a 100644
--- a/libc/include/android/api-level.h
+++ b/libc/include/android/api-level.h
@@ -110,6 +110,9 @@
 /** Names the "R" API level (30), for comparison against `__ANDROID_API__`. */
 #define __ANDROID_API_R__ 30
 
+/** Names the "S" API level (31), for comparison against `__ANDROID_API__`. */
+#define __ANDROID_API_S__ 31
+
 /**
  * Returns the `targetSdkVersion` of the caller, or `__ANDROID_API_FUTURE__`
  * if there is no known target SDK version (for code not running in the