diff --git a/Makefile b/Makefile
index 8aa489f3b6..d0ab8fdb04 100644
--- a/Makefile
+++ b/Makefile
@@ -342,6 +342,9 @@ include shared.mak
 # If it isn't set, fallback to $LC_ALL, $LANG or use the first utf-8
 # locale returned by "locale -a".
 #
+# Define TEST_CONTRIB_TOO to make "make test" run tests in contrib/
+# directories.
+#
 # Define HAVE_CLOCK_GETTIME if your platform has clock_gettime.
 #
 # Define HAVE_CLOCK_MONOTONIC if your platform has CLOCK_MONOTONIC.
@@ -3369,6 +3372,9 @@ export TEST_NO_MALLOC_CHECK
 
 test: all
 	$(MAKE) -C t/ all
+ifdef TEST_CONTRIB_TOO
+	$(MAKE) -C contrib/ test
+endif
 
 perf: all
 	$(MAKE) -C t/perf/ all
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index 8bda62b921..28cfe730ee 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -5,6 +5,8 @@
 
 . ${0%/*}/lib.sh
 
+export TEST_CONTRIB_TOO=yes
+
 case "$jobname" in
 fedora-breaking-changes-musl|linux-breaking-changes)
 	export WITH_BREAKING_CHANGES=YesPlease
@@ -36,6 +38,7 @@ linux-sha256)
 linux-reftable|linux-reftable-leaks|osx-reftable)
 	export GIT_TEST_DEFAULT_REF_FORMAT=reftable
 	;;
+
 esac
 
 case "$jobname" in
diff --git a/contrib/Makefile b/contrib/Makefile
new file mode 100644
index 0000000000..787cd07f52
--- /dev/null
+++ b/contrib/Makefile
@@ -0,0 +1,10 @@
+all::
+
+test::
+	$(MAKE) -C diff-highlight $@
+	$(MAKE) -C subtree $@
+
+clean::
+	$(MAKE) -C contacts $@
+	$(MAKE) -C diff-highlight $@
+	$(MAKE) -C subtree $@