diff --git a/docs/about/release-notes.md b/docs/about/release-notes.md
index 115237eb..6465eeb7 100644
--- a/docs/about/release-notes.md
+++ b/docs/about/release-notes.md
@@ -63,6 +63,7 @@ your global navigation uses more than one level, things will likely be broken.
 * Bugfix: Ensure theme files do not override `docs_dir` files (#1671).
 * Bugfix: Do not normalize URL fragments (#1655).
 * Bugfix: Skip external URLs in sitemap.xml (#1742).
+* Bugfix: Ensure theme files do not override docs_dir files on Windows (#1876)
 * Add canonical tag to `readthedocs` theme (#1669).
 
 ## Version 1.0.4 (2018-09-07)
diff --git a/mkdocs/structure/files.py b/mkdocs/structure/files.py
index 76d840f0..013a51b2 100644
--- a/mkdocs/structure/files.py
+++ b/mkdocs/structure/files.py
@@ -75,6 +75,7 @@ class Files(object):
             return True
         for path in env.list_templates(filter_func=filter):
             # Theme files do not override docs_dir files
+            path = os.path.normpath(path)
             if path not in self:
                 for dir in config['theme'].dirs:
                     # Find the first theme dir which contains path