diff --git a/CMakeLists.txt b/CMakeLists.txt
index 52e20ee2bdb..28234cd996b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,10 @@
 #
 #######################
 
+# Adjust default RelWithDebInfo flags to be in line with "Release with Debug".
+# The default RelWithDebInfo uses -O2, but Release uses -O3. This difference can be astonishing to users
+set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -g -DNDEBUG")
+
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_BINARY_DIR)
   message(FATAL_ERROR "In source builds are disabled.  Use a preset, -B or run from a different directory")
 endif()