diff --git a/lldb/CMakeLists.txt b/lldb/CMakeLists.txt
index 7844d93d78d29..b0764f1053277 100644
--- a/lldb/CMakeLists.txt
+++ b/lldb/CMakeLists.txt
@@ -75,6 +75,14 @@ if (LLDB_ENABLE_PYTHON)
       endif()
     endif()
   endforeach()
+  # Make sure lldb extension has "_d" suffix on Windows in Debug mode.
+  if(WIN32 AND CMAKE_BUILD_TYPE STREQUAL Debug)
+    string(SUBSTRING ${LLDB_PYTHON_EXT_SUFFIX} 0 2 FIRST_2_CHARS)
+    # Add "_d" manually if LLDB_PYTHON_EXT_SUFFIX lacks it due to release Python configuration.
+    if(NOT FIRST_2_CHARS STREQUAL "_d")
+      set(LLDB_PYTHON_EXT_SUFFIX "_d${LLDB_PYTHON_EXT_SUFFIX}")
+    endif()
+  endif()
 endif ()
 
 if (LLDB_ENABLE_LUA)