diff --git a/cli/CMakeLists.txt b/cli/CMakeLists.txt
index 0221817d9..728062ccd 100644
--- a/cli/CMakeLists.txt
+++ b/cli/CMakeLists.txt
@@ -6,11 +6,11 @@ list(REMOVE_ITEM srcs ${mainfile})
 add_library(cli_objs OBJECT ${hdrs} ${srcs})
 target_include_directories(cli_objs PRIVATE ${PROJECT_SOURCE_DIR}/lib/)
 if(USE_BUNDLED_TINYXML2)
-    target_include_directories(cli_objs PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
+    target_externals_include_directories(cli_objs PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
 else()
     target_include_directories(cli_objs SYSTEM PRIVATE ${tinyxml2_INCLUDE_DIRS})
 endif()
-target_include_directories(cli_objs PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
+target_externals_include_directories(cli_objs PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
 if (NOT CMAKE_DISABLE_PRECOMPILE_HEADERS)
     target_precompile_headers(cli_objs PRIVATE precompiled.h)
 endif()
@@ -38,11 +38,11 @@ endif()
 add_executable(cppcheck ${cppcheck_SOURCES})
 target_include_directories(cppcheck PRIVATE ${PROJECT_SOURCE_DIR}/lib/)
 if(USE_BUNDLED_TINYXML2)
-    target_include_directories(cppcheck PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
+    target_externals_include_directories(cppcheck PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
 else()
     target_include_directories(cppcheck SYSTEM PRIVATE ${tinyxml2_INCLUDE_DIRS})
 endif()
-target_include_directories(cppcheck PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
+target_externals_include_directories(cppcheck PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
 if (HAVE_RULES)
     target_link_libraries(cppcheck ${PCRE_LIBRARY})
 endif()
diff --git a/cmake/compileroptions.cmake b/cmake/compileroptions.cmake
index 5d4f67b1b..23c51be4f 100644
--- a/cmake/compileroptions.cmake
+++ b/cmake/compileroptions.cmake
@@ -16,6 +16,14 @@ function(target_compile_options_safe TARGET FLAG)
     endif()
 endfunction()
 
+function(target_externals_include_directories TARGET)
+    if (EXTERNALS_AS_SYSTEM)
+        target_include_directories(${TARGET} SYSTEM ${ARGN})
+    else()
+        target_include_directories(${TARGET} ${ARGN})
+    endif()
+endfunction()
+
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     add_compile_options(-Weverything)
 endif()
diff --git a/cmake/options.cmake b/cmake/options.cmake
index 00b639de7..8083532d0 100644
--- a/cmake/options.cmake
+++ b/cmake/options.cmake
@@ -17,7 +17,9 @@ option(ANALYZE_ADDRESS      "Clang dynamic analyzer: fast memory error detector.
 option(ANALYZE_THREAD       "Clang dynamic analyzer: tool that detects data races. "        OFF)
 option(ANALYZE_UNDEFINED    "Clang dynamic analyzer: undefined behavior checker. "          OFF)
 option(ANALYZE_DATAFLOW     "Clang dynamic analyzer: general dynamic dataflow analysis."    OFF)
+
 option(WARNINGS_ARE_ERRORS  "Treat warnings as errors"                                      OFF)
+option(EXTERNALS_AS_SYSTEM  "Treat externals as system includes"                            OFF)
 
 set(USE_MATCHCOMPILER "Auto" CACHE STRING "Usage of match compiler")
 set_property(CACHE USE_MATCHCOMPILER PROPERTY STRINGS Auto Off On Verify) 
diff --git a/cmake/printInfo.cmake b/cmake/printInfo.cmake
index edef367f7..3ccc78db5 100644
--- a/cmake/printInfo.cmake
+++ b/cmake/printInfo.cmake
@@ -25,7 +25,9 @@ message( STATUS "ANALYZE_ADDRESS =       ${ANALYZE_ADDRESS}" )
 message( STATUS "ANALYZE_THREAD =        ${ANALYZE_THREAD}" )
 message( STATUS "ANALYZE_UNDEFINED =     ${ANALYZE_UNDEFINED}" )
 message( STATUS "ANALYZE_DATAFLOW =      ${ANALYZE_DATAFLOW}" )
+message( STATUS )
 message( STATUS "WARNINGS_ARE_ERRORS =   ${WARNINGS_ARE_ERRORS}" )
+message( STATUS "EXTERNALS_AS_SYSTEM =   ${EXTERNALS_AS_SYSTEM}" )
 message( STATUS )
 message( STATUS "USE_MATCHCOMPILER =     ${USE_MATCHCOMPILER}" )
 message( STATUS "USE_MATCHCOMPILER_OPT = ${USE_MATCHCOMPILER_OPT}" )
diff --git a/gui/CMakeLists.txt b/gui/CMakeLists.txt
index d7fb05911..31fe62eaf 100644
--- a/gui/CMakeLists.txt
+++ b/gui/CMakeLists.txt
@@ -38,7 +38,7 @@ CheckOptions:
     set_target_properties(cppcheck-gui PROPERTIES WIN32_EXECUTABLE ON)
     target_include_directories(cppcheck-gui PRIVATE ${PROJECT_SOURCE_DIR}/lib/)
     if(USE_BUNDLED_TINYXML2)
-        target_include_directories(cppcheck-gui PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
+        target_externals_include_directories(cppcheck-gui PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
     else()
         target_include_directories(cppcheck-gui SYSTEM PRIVATE ${tinyxml2_INCLUDE_DIRS})
     endif()
diff --git a/gui/test/filelist/CMakeLists.txt b/gui/test/filelist/CMakeLists.txt
index 5b3413a14..4131b3316 100644
--- a/gui/test/filelist/CMakeLists.txt
+++ b/gui/test/filelist/CMakeLists.txt
@@ -10,7 +10,8 @@ add_executable(test-filelist
         ${CMAKE_SOURCE_DIR}/lib/utils.cpp
         $<TARGET_OBJECTS:simplecpp_objs>
         )
-target_include_directories(test-filelist PRIVATE ${CMAKE_SOURCE_DIR}/gui ${CMAKE_SOURCE_DIR}/lib ${CMAKE_SOURCE_DIR}/externals/simplecpp)
+target_include_directories(test-filelist PRIVATE ${CMAKE_SOURCE_DIR}/gui ${CMAKE_SOURCE_DIR}/lib)
+target_externals_include_directories(test-filelist PRIVATE ${CMAKE_SOURCE_DIR}/externals/simplecpp)
 target_compile_definitions(test-filelist PRIVATE SRCDIR="${CMAKE_CURRENT_SOURCE_DIR}")
 target_link_libraries(test-filelist ${QT_CORE_LIB} ${QT_TEST_LIB})
 
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index bd0a77dde..cd08c0e42 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -43,14 +43,14 @@ if (BUILD_CORE_DLL)
 else()
     add_library(cppcheck-core OBJECT ${srcs_lib} ${hdrs})
 endif()
-target_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/)
+target_externals_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/)
 if(USE_BUNDLED_TINYXML2)
-    target_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
+    target_externals_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2/)
 else()
     target_include_directories(cppcheck-core SYSTEM PRIVATE ${tinyxml2_INCLUDE_DIRS})
 endif()
-target_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/picojson/)
-target_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
+target_externals_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/picojson/)
+target_externals_include_directories(cppcheck-core PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
 if (HAVE_RULES)
     target_include_directories(cppcheck-core SYSTEM PRIVATE ${PCRE_INCLUDE})
 endif()
diff --git a/releasenotes.txt b/releasenotes.txt
index 0db51f000..887223c85 100644
--- a/releasenotes.txt
+++ b/releasenotes.txt
@@ -16,4 +16,4 @@ Deprecations:
 -
 
 Other:
--
+- Added CMake option 'EXTERNALS_AS_SYSTEM' to treat external includes as 'SYSTEM' ones.
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index e99afca4e..26d76976e 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -12,11 +12,11 @@ if (BUILD_TESTS)
     add_executable(testrunner ${testrunner_SOURCES})
     target_include_directories(testrunner PRIVATE ${PROJECT_SOURCE_DIR}/lib/ ${PROJECT_SOURCE_DIR}/cli/)
     if(USE_BUNDLED_TINYXML2)
-        target_include_directories(testrunner PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2)
+        target_externals_include_directories(testrunner PRIVATE ${PROJECT_SOURCE_DIR}/externals/tinyxml2)
     else()
         target_include_directories(testrunner SYSTEM PRIVATE ${tinyxml2_INCLUDE_DIRS})
     endif()
-    target_include_directories(testrunner PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
+    target_externals_include_directories(testrunner PRIVATE ${PROJECT_SOURCE_DIR}/externals/simplecpp/)
     if (HAVE_RULES)
         target_link_libraries(testrunner ${PCRE_LIBRARY})
     endif()
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index ce5eb2821..4f9ea9d70 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -17,7 +17,8 @@ add_executable(dmake EXCLUDE_FROM_ALL
         ${CMAKE_SOURCE_DIR}/lib/utils.cpp
         $<TARGET_OBJECTS:simplecpp_objs>
 )
-target_include_directories(dmake PRIVATE ${CMAKE_SOURCE_DIR}/cli ${CMAKE_SOURCE_DIR}/lib ${CMAKE_SOURCE_DIR}/externals/simplecpp)
+target_include_directories(dmake PRIVATE ${CMAKE_SOURCE_DIR}/cli ${CMAKE_SOURCE_DIR}/lib)
+target_externals_include_directories(dmake PRIVATE ${CMAKE_SOURCE_DIR}/externals/simplecpp)
 if (WIN32 AND NOT BORLAND)
     if(NOT MINGW)
         target_link_libraries(dmake Shlwapi.lib)