diff --git a/Makefile b/Makefile
index d35f08f..6421b72 100644
--- a/Makefile
+++ b/Makefile
@@ -93,7 +93,7 @@ workshop-check :
 ## III. Commands specific to lesson websites
 ## =================================================
 
-.PHONY : lesson-check lesson-md lesson-files lesson-fixme install-rmd-deps
+.PHONY : lesson-check lesson-md lesson-files lesson-fixme lesson-check-all install-rmd-deps
 
 # RMarkdown files
 RMD_SRC = $(wildcard _episodes_rmd/??-*.Rmd)