diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8a8ec226e0..a6d5a9e810 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,16 +5,21 @@ if(NOT CMAKE_BUILD_TYPE)
         "Choose the type of build, options are: None Debug Release RelWithDebInfo MinSizeRel." FORCE)
 endif()
 
-set(_list "None;Debug;Release;RelWithDebInfo;MinSizeRel")
-list(FIND _list ${CMAKE_BUILD_TYPE} _index)
-if(${_index} EQUAL -1)
-    string(REPLACE ";" ", " _list_pretty "${_list}")
-    message("::")
-    message(":: ERROR: Invalid build type: ${CMAKE_BUILD_TYPE}")
-    message("::")
-    message(":: valid types: { ${_list_pretty} }")
-    message("::")
-    message(FATAL_ERROR)
+set(_list "Debug;Release;RelWithDebInfo;MinSizeRel")
+string(TOLOWER "${_list}" _list_lower)
+string(TOLOWER ${CMAKE_BUILD_TYPE} _build_type_lower)
+list(FIND _list_lower "${_build_type_lower}" _index)
+if(NOT ${_index} EQUAL -1)
+    list(FIND _list "${CMAKE_BUILD_TYPE}" _index)
+    if(${_index} EQUAL -1)
+        string(REPLACE ";" ", " _list_pretty "${_list}")
+        message("::")
+        message(":: ERROR: build type case-mismatch: ${CMAKE_BUILD_TYPE}")
+        message("::")
+        message(":: valid types: { ${_list_pretty} }")
+        message("::")
+        message(FATAL_ERROR)
+    endif()
 endif()
 
 if(NOT CMAKE_INSTALL_PREFIX)