diff --git a/README.md b/README.md
index 9addbe68..b3f6967c 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,12 @@ The Language stats bar displays languages percentages for the files in the repos
 0. If the files are being misclassified, search for [open issues][issues] to see if anyone else has already reported the issue. Any information you can add, especially links to public repositories, is helpful.
 0. If there are no reported issues of this misclassification, [open an issue][new-issue] and include a link to the repository or a sample of the code that is being misclassified.
 
+### There's a problem with the syntax highlighting of a file
+
+Linguist detects the language of a file but the actual syntax-highlighting is powered by a set of language grammars which are included in this project as a set of submodules [and may be found here](https://github.com/github/linguist/blob/master/vendor/README.md).
+
+If you experience an issue with the syntax-highlighting on GitHub, **please report the issue to the upstream grammar repository, not here.** Grammars are updated every time we build the Linguist gem and so upstream bug fixes are automatically incorporated as they are fixed.
+
 ## Overrides
 
 Linguist supports a number of different custom overrides strategies for language definitions and vendored paths.