diff --git a/CMakeLists.txt b/CMakeLists.txt
index ea88454d227..aea8dcfdf87 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -445,6 +445,7 @@ if(NOT MSVC)
   # Details at http://eigen.tuxfamily.org/bz/show_bug.cgi?id=1459
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wextra")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=return-type")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-missing-field-initializers")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-type-limits")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-array-bounds")