diff --git a/src/openrct2-android/app/src/main/CMakeLists.txt b/src/openrct2-android/app/src/main/CMakeLists.txt
index 7b0c331fbe..8dc2be331a 100644
--- a/src/openrct2-android/app/src/main/CMakeLists.txt
+++ b/src/openrct2-android/app/src/main/CMakeLists.txt
@@ -124,9 +124,9 @@ set_target_properties(crypto PROPERTIES IMPORTED_LOCATION
 add_dependencies(crypto libs)
 
 
-include_directories("${CMAKE_BINARY_DIR}/libs/include")
-include_directories("${CMAKE_BINARY_DIR}/libs/include/freetype2")
-include_directories("${CMAKE_BINARY_DIR}/libs/include/SDL2")
+include_directories(SYSTEM "${CMAKE_BINARY_DIR}/libs/include")
+include_directories(SYSTEM "${CMAKE_BINARY_DIR}/libs/include/freetype2")
+include_directories(SYSTEM "${CMAKE_BINARY_DIR}/libs/include/SDL2")
 
 # now build app's shared lib
 include_directories(./ndk_helper
diff --git a/src/openrct2/CMakeLists.txt b/src/openrct2/CMakeLists.txt
index da65bbb93f..aff74307f9 100644
--- a/src/openrct2/CMakeLists.txt
+++ b/src/openrct2/CMakeLists.txt
@@ -40,7 +40,7 @@ if (NOT DISABLE_NETWORK OR NOT DISABLE_HTTP)
 
         find_package(OpenSSL 1.0.0 REQUIRED)
 
-        target_include_directories(${PROJECT_NAME} PUBLIC ${OPENSSL_INCLUDE_DIR})
+        target_include_directories(${PROJECT_NAME} SYSTEM PUBLIC ${OPENSSL_INCLUDE_DIR})
 
         if(STATIC)
             target_link_libraries(${PROJECT_NAME} ${SSL_STATIC_LIBRARIES})
@@ -60,7 +60,7 @@ if (NOT DISABLE_HTTP)
     else ()
         PKG_CHECK_MODULES(LIBCURL REQUIRED libcurl)
 
-        target_include_directories(${PROJECT_NAME} PRIVATE ${LIBCURL_INCLUDE_DIRS})
+        target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${LIBCURL_INCLUDE_DIRS})
 
         if (STATIC)
             target_link_libraries(${PROJECT_NAME} ${LIBCURL_STATIC_LIBRARIES})
@@ -81,10 +81,10 @@ if (NOT DISABLE_TTF)
         PKG_CHECK_MODULES(FREETYPE REQUIRED freetype2)
     endif ()
         
-    target_include_directories(${PROJECT_NAME} PRIVATE ${FREETYPE_INCLUDE_DIRS})
+    target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${FREETYPE_INCLUDE_DIRS})
         
     if (UNIX AND NOT APPLE)
-        target_include_directories(${PROJECT_NAME} PRIVATE ${FONTCONFIG_INCLUDE_DIRS})
+        target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${FONTCONFIG_INCLUDE_DIRS})
     endif ()
 endif ()
 
@@ -94,7 +94,7 @@ if (NOT DISABLE_GOOGLE_BENCHMARK)
         message("Found Google benchmark, enabling support")
         set_target_properties(${PROJECT_NAME} PROPERTIES COMPILE_DEFINITIONS USE_BENCHMARK)
         target_link_libraries(${PROJECT_NAME} benchmark::benchmark)
-        target_include_directories(${PROJECT_NAME} PRIVATE ${benchmark_INCLUDE_DIRS})
+        target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${benchmark_INCLUDE_DIRS})
     else ()
         message("Google benchmark not found, disabling support")
     endif ()
@@ -199,9 +199,9 @@ if (HAVE_DISCORD_RPC)
 endif()
 
 # Includes
-target_include_directories(${PROJECT_NAME} PRIVATE ${LIBZIP_INCLUDE_DIRS})
-target_include_directories(${PROJECT_NAME} PRIVATE ${PNG_INCLUDE_DIRS}
-                                                   ${ZLIB_INCLUDE_DIRS})
+target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${LIBZIP_INCLUDE_DIRS})
+target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${PNG_INCLUDE_DIRS}
+                                                          ${ZLIB_INCLUDE_DIRS})
 include_directories(${PROJECT_NAME} SYSTEM ${CMAKE_CURRENT_LIST_DIR}/../thirdparty)
 
 # To avoid unnecessary rebuilds set the current branch and
diff --git a/test/tests/CMakeLists.txt b/test/tests/CMakeLists.txt
index aabb5f3d45..94b994f3ab 100644
--- a/test/tests/CMakeLists.txt
+++ b/test/tests/CMakeLists.txt
@@ -67,7 +67,7 @@ endif (SYSTEM_GTEST)
 
 include_directories(SYSTEM ${GTEST_INCLUDE_DIRS})
 include_directories("${ROOT_DIR}/src")
-include_directories(${SDL2_INCLUDE_DIRS})
+include_directories(SYSTEM ${SDL2_INCLUDE_DIRS})
 
 # Some most common files required in tests
 set(COMMON_TEST_SOURCES