diff --git a/doc/guides/releases.md b/doc/guides/releases.md
index 9bd0992fcc17d3..d4f2a2ac962771 100644
--- a/doc/guides/releases.md
+++ b/doc/guides/releases.md
@@ -283,7 +283,7 @@ in the release branch (e.g. a release for Node.js v4 would be added to the
 
 The new entry should take the following form:
 
-```md
+```markdown
 <a id="x.y.x"></a>
 ## YYYY-MM-DD, Version x.y.z (Release Type), @releaser
 
diff --git a/tools/doc/README.md b/tools/doc/README.md
index 3679c2c23df6e2..f2f37faa653d4d 100644
--- a/tools/doc/README.md
+++ b/tools/doc/README.md
@@ -4,7 +4,7 @@ Here's how the node docs work.
 
 Each type of heading has a description block.
 
-```md
+```markdown
 # module
 
 <!--introduced_in=v0.10.0-->