diff --git a/.gitattributes b/.gitattributes
index 1adc275f..670b63eb 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -5,3 +5,5 @@ Rakefile linguist-generated
 test/fixtures/* linguist-vendored=false
 README.md linguist-documentation=false
 samples/Arduino/* linguist-documentation
+samples/Markdown/*.md linguist-detectable=true
+samples/HTML/*.html linguist-detectable=false