diff --git a/lib/mini_portile2/mini_portile_cmake.rb b/lib/mini_portile2/mini_portile_cmake.rb
index 8543645..fd7aa08 100644
--- a/lib/mini_portile2/mini_portile_cmake.rb
+++ b/lib/mini_portile2/mini_portile_cmake.rb
@@ -69,7 +69,8 @@ def cmake_compile_flags
       "-DCMAKE_SYSTEM_NAME=#{cmake_system_name}",
       "-DCMAKE_SYSTEM_PROCESSOR=#{cpu_type}",
       "-DCMAKE_C_COMPILER=#{c_compiler}",
-      "-DCMAKE_CXX_COMPILER=#{cxx_compiler}"
+      "-DCMAKE_CXX_COMPILER=#{cxx_compiler}",
+      "-DCMAKE_BUILD_TYPE=Release"
     ]
   end