diff --git a/CMakeLists.txt b/CMakeLists.txt
index fe69cf3a9d..8909de65d2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,6 +17,15 @@ if(NOT CMAKE_CONFIGURATION_TYPES)
     endif()
 endif()
 
+# https://blog.kitware.com/cmake-and-the-default-build-type/
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+    set(default_build_type "Debug")
+    message(STATUS "Setting build type to '${default_build_type}' as none was specified.")
+    set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE STRING "Choose the type of build." FORCE)
+    # Set the possible values of build type for cmake-gui
+    set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release")
+endif()
+
 if(APPLE AND NOT CMAKE_OSX_DEPLOYMENT_TARGET)
     # If no deployment target has been set default to the minimum supported
     # OS X version (this has to be set before the first project() call)