diff --git a/ngraph/CMakeLists.txt b/ngraph/CMakeLists.txt
index f975bb87efb..6163c01e4a7 100644
--- a/ngraph/CMakeLists.txt
+++ b/ngraph/CMakeLists.txt
@@ -200,27 +200,6 @@ if (LINUX)
     endif()
 endif()
 
-#-----------------------------------------------------------------------------------------------
-# Compile Flags to pass to external projects...
-#-----------------------------------------------------------------------------------------------
-
-if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    if (DEFINED NGRAPH_USE_CXX_ABI)
-        message( STATUS "nGraph using CXX11 ABI: " ${NGRAPH_USE_CXX_ABI} )
-        list(APPEND NGRAPH_COMMON_FLAGS -D_GLIBCXX_USE_CXX11_ABI=${NGRAPH_USE_CXX_ABI})
-    endif()
-endif()
-
-string(REPLACE " " ";" NGRAPH_CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-string(REPLACE " " ";" NGRAPH_CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-list(APPEND NGRAPH_COMMON_CXX_FLAGS ${NGRAPH_CMAKE_CXX_FLAGS} ${NGRAPH_COMMON_FLAGS})
-list(APPEND NGRAPH_COMMON_C_FLAGS ${NGRAPH_CMAKE_C_FLAGS} ${NGRAPH_COMMON_FLAGS})
-message(STATUS "NGRAPH_COMMON_CXX_FLAGS ${NGRAPH_COMMON_CXX_FLAGS}")
-message(STATUS "NGRAPH_COMMON_C_FLAGS ${NGRAPH_COMMON_C_FLAGS}")
-
-# Set baseline flags for nGraph source files
-string(REPLACE ";" " " CMAKE_ORIGINAL_CXX_FLAGS "${NGRAPH_COMMON_CXX_FLAGS}")
-
 #-----------------------------------------------------------------------------------------------
 # Compile Flags for nGraph...
 #-----------------------------------------------------------------------------------------------
diff --git a/ngraph/cmake/external_gtest.cmake b/ngraph/cmake/external_gtest.cmake
index 49322513fb8..7401f9af8d0 100644
--- a/ngraph/cmake/external_gtest.cmake
+++ b/ngraph/cmake/external_gtest.cmake
@@ -42,15 +42,7 @@ if(CMAKE_BUILD_TYPE)
     )
 endif()
 
-if(UNIX)
-    # workaround for compile error
-    # related: https://github.com/intel/mkl-dnn/issues/55
-    set(GTEST_CXX_FLAGS "-Wno-unused-result ${CMAKE_ORIGINAL_CXX_FLAGS} -Wno-undef")
-else()
-    set(GTEST_CXX_FLAGS ${CMAKE_ORIGINAL_CXX_FLAGS})
-endif()
-
-#Build for ninja
+# Build for ninja
 SET(GTEST_PATHS ${GTEST_OUTPUT_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gtestd${CMAKE_STATIC_LIBRARY_SUFFIX}
     ${GMOCK_OUTPUT_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gmockd${CMAKE_STATIC_LIBRARY_SUFFIX}
     ${GTEST_OUTPUT_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gtest${CMAKE_STATIC_LIBRARY_SUFFIX}
diff --git a/ngraph/cmake/external_onnx.cmake b/ngraph/cmake/external_onnx.cmake
index 48c91065601..f50f48dd932 100644
--- a/ngraph/cmake/external_onnx.cmake
+++ b/ngraph/cmake/external_onnx.cmake
@@ -26,16 +26,10 @@ set(ONNX_VERSION 1.8.1)
 # Download and install libonnx ...
 #------------------------------------------------------------------------------
 
-# Since this file is going to be modifying CMAKE_CXX_FLAGS we need to preserve
-# it so we won't overwrite the caller's CMAKE_CXX_FLAGS
-set(PUSH_CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
-
 set(ONNX_GIT_REPO_URL https://github.com/onnx/onnx.git)
 set(ONNX_GIT_BRANCH rel-${ONNX_VERSION})
 set(NGRAPH_ONNX_NAMESPACE ngraph_onnx)
 
-set(CMAKE_CXX_FLAGS ${CMAKE_ORIGINAL_CXX_FLAGS})
-
 FetchContent_Declare(
     ext_onnx
     GIT_REPOSITORY ${ONNX_GIT_REPO_URL}
@@ -77,6 +71,3 @@ endif()
 
 set(ONNX_INCLUDE_DIR ${ext_onnx_SOURCE_DIR})
 set(ONNX_PROTO_INCLUDE_DIR ${ext_onnx_BINARY_DIR})
-
-# Now make sure we restore the original CMAKE_CXX_FLAGS for the caller
-set(CMAKE_CXX_FLAGS ${PUSH_CMAKE_CXX_FLAGS})