diff --git a/CMakeLists.txt b/CMakeLists.txt
index e69de4d5..fa226830 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -144,6 +144,20 @@ endif()
 # Random other things
 if(WIN32)
   add_definitions(-D_WEBSOCKETPP_CPP11_STL_)
+
+  # Set the correct Windows preprocessor var for asio 
+  macro(get_WIN32_WINNT version)
+    if (WIN32 AND CMAKE_SYSTEM_VERSION)
+      set(ver ${CMAKE_SYSTEM_VERSION})
+      string(REPLACE "." "" ver ${ver})
+      string(REGEX REPLACE "([0-9])" "0\\1" ver ${ver})
+
+      set(${version} "0x${ver}")
+    endif()
+  endmacro()
+
+  get_WIN32_WINNT(ver)
+  add_definitions(-D_WIN32_WINNT=${ver})
 elseif(UNIX AND NOT APPLE)
   target_compile_options(
     obs-websocket PRIVATE -Wall -Wextra -Wno-missing-field-initializers