diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4acc9d5a..ebd989fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.9)
 project(aws-c-s3 C)
 
 option(ASSERT_LOCK_HELD "Enable ASSERT_SYNCED_DATA_LOCK_HELD for checking thread issue" OFF)