diff --git a/Makefile b/Makefile
index 7e44b67599..1a31f65bfd 100644
--- a/Makefile
+++ b/Makefile
@@ -2159,6 +2159,9 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@
 	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@
 	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@
+ifdef TEST_OUTPUT_DIRECTORY
+	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@
+endif
 ifdef GIT_TEST_OPTS
 	@echo GIT_TEST_OPTS=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_OPTS)))'\' >>$@
 endif
diff --git a/t/Makefile b/t/Makefile
index 44ca7d32dc..2373a04f7a 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -15,9 +15,16 @@ PROVE ?= prove
 DEFAULT_TEST_TARGET ?= test
 TEST_LINT ?= test-lint-duplicates test-lint-executable
 
+ifdef TEST_OUTPUT_DIRECTORY
+TEST_RESULTS_DIRECTORY = $(TEST_OUTPUT_DIRECTORY)/test-results
+else
+TEST_RESULTS_DIRECTORY = test-results
+endif
+
 # Shell quote;
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
 PERL_PATH_SQ = $(subst ','\'',$(PERL_PATH))
+TEST_RESULTS_DIRECTORY_SQ = $(subst ','\'',$(TEST_RESULTS_DIRECTORY))
 
 T = $(sort $(wildcard t[0-9][0-9][0-9][0-9]-*.sh))
 TSVN = $(sort $(wildcard t91[0-9][0-9]-*.sh))
@@ -36,10 +43,10 @@ $(T):
 	@echo "*** $@ ***"; GIT_CONFIG=.git/config '$(SHELL_PATH_SQ)' $@ $(GIT_TEST_OPTS)
 
 pre-clean:
-	$(RM) -r test-results
+	$(RM) -r '$(TEST_RESULTS_DIRECTORY_SQ)'
 
 clean-except-prove-cache:
-	$(RM) -r 'trash directory'.* test-results
+	$(RM) -r 'trash directory'.* '$(TEST_RESULTS_DIRECTORY_SQ)'
 	$(RM) -r valgrind/bin
 
 clean: clean-except-prove-cache
@@ -65,7 +72,7 @@ aggregate-results-and-cleanup: $(T)
 	$(MAKE) clean
 
 aggregate-results:
-	for f in test-results/t*-*.counts; do \
+	for f in '$(TEST_RESULTS_DIRECTORY_SQ)'/t*-*.counts; do \
 		echo "$$f"; \
 	done | '$(SHELL_PATH_SQ)' ./aggregate-results.sh
 
diff --git a/t/test-lib.sh b/t/test-lib.sh
index ca6bdef63d..eff3a653d1 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -54,8 +54,8 @@ done,*)
 	# do not redirect again
 	;;
 *' --tee '*|*' --va'*)
-	mkdir -p test-results
-	BASE=test-results/$(basename "$0" .sh)
+	mkdir -p "$TEST_OUTPUT_DIRECTORY/test-results"
+	BASE="$TEST_OUTPUT_DIRECTORY/test-results/$(basename "$0" .sh)"
 	(GIT_TEST_TEE_STARTED=done ${SHELL_PATH} "$0" "$@" 2>&1;
 	 echo $? > $BASE.exit) | tee $BASE.out
 	test "$(cat $BASE.exit)" = 0
diff --git a/t/valgrind/analyze.sh b/t/valgrind/analyze.sh
index d8105d9fab..2ffc80f721 100755
--- a/t/valgrind/analyze.sh
+++ b/t/valgrind/analyze.sh
@@ -1,6 +1,10 @@
 #!/bin/sh
 
-out_prefix=$(dirname "$0")/../test-results/valgrind.out
+# Get TEST_OUTPUT_DIRECTORY from GIT-BUILD-OPTIONS if it's there...
+. "$(dirname "$0")/../../GIT-BUILD-OPTIONS"
+# ... otherwise set it to the default value.
+: ${TEST_OUTPUT_DIRECTORY=$(dirname "$0")/..}
+
 output=
 count=0
 total_count=0
@@ -115,7 +119,7 @@ handle_one () {
 	finish_output
 }
 
-for test_script in "$(dirname "$0")"/../test-results/*.out
+for test_script in "$TEST_OUTPUT_DIRECTORY"/test-results/*.out
 do
 	handle_one $test_script
 done