diff --git a/README.md b/README.md
index cb4b043655..68063d9f86 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,7 @@ documentation.
 
 ```
 gcc-6+ binutils bzip2 flex python3 perl make4.1+ find grep diff unzip gawk getopt
-subversion libz-dev libc-dev rsync
+subversion libz-dev libc-dev rsync which
 ```
 
 ### Quickstart
diff --git a/include/prereq-build.mk b/include/prereq-build.mk
index bbeba3f8ff..32edc6e437 100644
--- a/include/prereq-build.mk
+++ b/include/prereq-build.mk
@@ -166,6 +166,9 @@ $(eval $(call SetupHostCommand,file,Please install the 'file' package, \
 $(eval $(call SetupHostCommand,rsync,Please install 'rsync', \
 	rsync --version </dev/null))
 
+$(eval $(call SetupHostCommand,which,Please install 'which', \
+	which which | grep which))
+
 $(STAGING_DIR_HOST)/bin/mkhash: $(SCRIPT_DIR)/mkhash.c
 	mkdir -p $(dir $@)
 	$(CC) -O2 -I$(TOPDIR)/tools/include -o $@ $<