diff --git a/CMakeLists.txt b/CMakeLists.txt
index a9be165f0..f2dc1f02d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -344,6 +344,11 @@ if(NOT WIN32)
     list(APPEND MAPNIK_OPTIONAL_LIBS ${CMAKE_DL_LIBS})
 endif()
 
+# force utf-8 source code processing
+# see https://docs.microsoft.com/de-de/cpp/build/reference/utf-8-set-source-and-executable-character-sets-to-utf-8?view=msvc-170
+add_compile_options("$<$<C_COMPILER_ID:MSVC>:/utf-8>")
+add_compile_options("$<$<CXX_COMPILER_ID:MSVC>:/utf-8>")
+
 add_library(core INTERFACE)
 add_library(mapnik::core ALIAS core)