diff --git a/cmake/macros/Interrogate.cmake b/cmake/macros/Interrogate.cmake
index 6cad20cac6..399b3acd20 100644
--- a/cmake/macros/Interrogate.cmake
+++ b/cmake/macros/Interrogate.cmake
@@ -228,6 +228,11 @@ function(interrogate_sources target output database language_flags)
     endif()
   endforeach(build_type)
 
+  # In case the user (or a distro buildsystem) is throwing NDEBUG in by hand:
+  if(CMAKE_CXX_FLAGS MATCHES ".*NDEBUG.*")
+    list(APPEND define_flags "-DNDEBUG")
+  endif()
+
   get_filename_component(output_directory "${output}" DIRECTORY)
   get_filename_component(database_directory "${database}" DIRECTORY)