diff --git a/tools/cmake/idf.cmake b/tools/cmake/idf.cmake
index e97d83fcd..2d396c886 100644
--- a/tools/cmake/idf.cmake
+++ b/tools/cmake/idf.cmake
@@ -1,19 +1,24 @@
 get_property(__idf_env_set GLOBAL PROPERTY __IDF_ENV_SET)
 if(NOT __idf_env_set)
     # Infer an IDF_PATH relative to the tools/cmake directory
-    get_filename_component(_idf_path "${CMAKE_CURRENT_LIST_DIR}/../.." ABSOLUTE)
+    get_filename_component(_idf_path "${CMAKE_CURRENT_LIST_DIR}/../.." REALPATH)
     file(TO_CMAKE_PATH "${_idf_path}" _idf_path)
 
     # Get the path set in environment
     set(idf_path $ENV{IDF_PATH})
-    file(TO_CMAKE_PATH "${idf_path}" idf_path)
 
     # Environment IDF_PATH should match the inferred IDF_PATH. If not, warn the user.
+    # (Note: REALPATH is needed in both above steps to account for case on case
+    # insensitive filesystems, or relative paths)
     if(idf_path)
+        get_filename_component(idf_path "${idf_path}" REALPATH)
+        file(TO_CMAKE_PATH "${idf_path}" idf_path)
+
         if(NOT idf_path STREQUAL _idf_path)
             message(WARNING "IDF_PATH environment variable is different from inferred IDF_PATH.
                             Check if your project's top-level CMakeLists.txt includes the right
-                            CMake files. Environment IDF_PATH will be used for the build.")
+                            CMake files. Environment IDF_PATH will be used for the build:
+                            ${idf_path}")
         endif()
     else()
         message(WARNING "IDF_PATH environment variable not found. Setting IDF_PATH to '${_idf_path}'.")
@@ -43,4 +48,4 @@ if(NOT __idf_env_set)
     __build_init("${idf_path}")
 
     set_property(GLOBAL PROPERTY __IDF_ENV_SET 1)
-endif()
\ No newline at end of file
+endif()