diff --git a/doc/FileExt.txt b/doc/FileExt.txt
index b9d7c159ed..52ddb8dd13 100644
--- a/doc/FileExt.txt
+++ b/doc/FileExt.txt
@@ -417,6 +417,7 @@ Markdown
 	mkd
 
 	litcoffee		Literate CoffeeScript
+	Rmd				R Markdown, https://rmarkdown.rstudio.com/
 
 Mathematica
 	m				Module
diff --git a/src/EditLexers/stlMarkdown.c b/src/EditLexers/stlMarkdown.c
index a65fa6fa5d..2a82688397 100644
--- a/src/EditLexers/stlMarkdown.c
+++ b/src/EditLexers/stlMarkdown.c
@@ -64,7 +64,7 @@ EDITLEXER lexMarkdown = {
 		0, 0,
 //Settings--Autogenerated -- end of section automatically generated
 	EDITLEXER_HOLE(L"Markdown", Styles_Markdown),
-	L"md; markdown; mdown; mkdn; mkd; litcoffee",
+	L"md; markdown; mdown; mkdn; mkd; litcoffee; rmd",
 	&Keywords_Markdown,
 	Styles_Markdown
 };