diff --git a/modules/safeguards.cmake b/modules/safeguards.cmake
index 39505a7..a613896 100644
--- a/modules/safeguards.cmake
+++ b/modules/safeguards.cmake
@@ -17,6 +17,7 @@ string(TOUPPER "${CMAKE_BUILD_TYPE}" cmake_build_type_toupper)
 
 if(NOT cmake_build_type_tolower STREQUAL "debug" AND
    NOT cmake_build_type_tolower STREQUAL "release" AND
+   NOT cmake_build_type_tolower STREQUAL "minsizerel" AND
    NOT cmake_build_type_tolower STREQUAL "relwithdebinfo")
-    message(FATAL_ERROR "Unknown build type \"${CMAKE_BUILD_TYPE}\". Allowed values are Debug, Release, RelWithDebInfo (case-insensitive).")
+    message(FATAL_ERROR "Unknown build type \"${CMAKE_BUILD_TYPE}\". Allowed values are Debug, Release, RelWithDebInfo, and MinSizeRel (case-insensitive).")
 endif()