diff --git a/t/Makefile b/t/Makefile
index ed49c20b16b520da1b460960dbadd5d31c4927ba..09623414a755dc7e964a0d21768e136dba4556e2 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -38,4 +38,7 @@ full-svn-test:
 	$(MAKE) $(TSVN) GIT_SVN_NO_OPTIMIZE_COMMITS=1 LC_ALL=C
 	$(MAKE) $(TSVN) GIT_SVN_NO_OPTIMIZE_COMMITS=0 LC_ALL=en_US.UTF-8
 
-.PHONY: pre-clean $(T) aggregate-results clean
+valgrind:
+	GIT_TEST_OPTS=--valgrind $(MAKE)
+
+.PHONY: pre-clean $(T) aggregate-results clean valgrind
diff --git a/t/README b/t/README
index f208cf1db972d580d977c356bb589cf6147247a7..d8f6c7de6d27e27a33982e82893baa3bb5ffd7fd 100644
--- a/t/README
+++ b/t/README
@@ -39,7 +39,8 @@ this:
     * passed all 3 test(s)
 
 You can pass --verbose (or -v), --debug (or -d), and --immediate
-(or -i) command line argument to the test.
+(or -i) command line argument to the test, or by setting GIT_TEST_OPTS
+appropriately before running "make".
 
 --verbose::
 	This makes the test more verbose.  Specifically, the
@@ -58,6 +59,21 @@ You can pass --verbose (or -v), --debug (or -d), and --immediate
 	This causes additional long-running tests to be run (where
 	available), for more exhaustive testing.
 
+--valgrind::
+	Execute all Git binaries with valgrind and exit with status
+	126 on errors (just like regular tests, this will only stop
+	the test script when running under -i).  Valgrind errors
+	go to stderr, so you might want to pass the -v option, too.
+
+	Since it makes no sense to run the tests with --valgrind and
+	not see any output, this option implies --verbose.  For
+	convenience, it also implies --tee.
+
+--tee::
+	In addition to printing the test output to the terminal,
+	write it to files named 't/test-results/$TEST_NAME.out'.
+	As the names depend on the tests' file names, it is safe to
+	run the tests with this option in parallel.
 
 Skipping Tests
 --------------
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 0c455929e4e52795e616c3e2635f5899dff665c2..7a847ecbde018f36911ee6a1074ba169af1f350d 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -3,6 +3,22 @@
 # Copyright (c) 2005 Junio C Hamano
 #
 
+# if --tee was passed, write the output not only to the terminal, but
+# additionally to the file test-results/$BASENAME.out, too.
+case "$GIT_TEST_TEE_STARTED, $* " in
+done,*)
+	# do not redirect again
+	;;
+*' --tee '*|*' --va'*)
+	mkdir -p test-results
+	BASE=test-results/$(basename "$0" .sh)
+	(GIT_TEST_TEE_STARTED=done ${SHELL-sh} "$0" "$@" 2>&1;
+	 echo $? > $BASE.exit) | tee $BASE.out
+	test "$(cat $BASE.exit)" = 0
+	exit
+	;;
+esac
+
 # Keep the original TERM for say_color
 ORIGINAL_TERM=$TERM
 
@@ -94,6 +110,10 @@ do
 	--no-python)
 		# noop now...
 		shift ;;
+	--va|--val|--valg|--valgr|--valgri|--valgrin|--valgrind)
+		valgrind=t; verbose=t; shift ;;
+	--tee)
+		shift ;; # was handled already
 	*)
 		break ;;
 	esac
@@ -434,7 +454,7 @@ test_create_repo () {
 	repo="$1"
 	mkdir -p "$repo"
 	cd "$repo" || error "Cannot setup test environment"
-	"$GIT_EXEC_PATH/git" init "--template=$GIT_EXEC_PATH/templates/blt/" >&3 2>&4 ||
+	"$GIT_EXEC_PATH/git" init "--template=$owd/../templates/blt/" >&3 2>&4 ||
 	error "cannot run git init -- have you built things yet?"
 	mv .git/hooks .git/hooks-disabled
 	cd "$owd"
@@ -492,8 +512,73 @@ test_done () {
 # Test the binaries we have just built.  The tests are kept in
 # t/ subdirectory and are run in 'trash directory' subdirectory.
 TEST_DIRECTORY=$(pwd)
-PATH=$TEST_DIRECTORY/..:$PATH
-GIT_EXEC_PATH=$(pwd)/..
+if test -z "$valgrind"
+then
+	PATH=$TEST_DIRECTORY/..:$PATH
+	GIT_EXEC_PATH=$TEST_DIRECTORY/..
+else
+	make_symlink () {
+		test -h "$2" &&
+		test "$1" = "$(readlink "$2")" || {
+			# be super paranoid
+			if mkdir "$2".lock
+			then
+				rm -f "$2" &&
+				ln -s "$1" "$2" &&
+				rm -r "$2".lock
+			else
+				while test -d "$2".lock
+				do
+					say "Waiting for lock on $2."
+					sleep 1
+				done
+			fi
+		}
+	}
+
+	make_valgrind_symlink () {
+		# handle only executables
+		test -x "$1" || return
+
+		base=$(basename "$1")
+		symlink_target=$TEST_DIRECTORY/../$base
+		# do not override scripts
+		if test -x "$symlink_target" &&
+		    test ! -d "$symlink_target" &&
+		    test "#!" != "$(head -c 2 < "$symlink_target")"
+		then
+			symlink_target=../valgrind.sh
+		fi
+		case "$base" in
+		*.sh|*.perl)
+			symlink_target=../unprocessed-script
+		esac
+		# create the link, or replace it if it is out of date
+		make_symlink "$symlink_target" "$GIT_VALGRIND/bin/$base" || exit
+	}
+
+	# override all git executables in TEST_DIRECTORY/..
+	GIT_VALGRIND=$TEST_DIRECTORY/valgrind
+	mkdir -p "$GIT_VALGRIND"/bin
+	for file in $TEST_DIRECTORY/../git* $TEST_DIRECTORY/../test-*
+	do
+		make_valgrind_symlink $file
+	done
+	OLDIFS=$IFS
+	IFS=:
+	for path in $PATH
+	do
+		ls "$path"/git-* 2> /dev/null |
+		while read file
+		do
+			make_valgrind_symlink "$file"
+		done
+	done
+	IFS=$OLDIFS
+	PATH=$GIT_VALGRIND/bin:$PATH
+	GIT_EXEC_PATH=$GIT_VALGRIND/bin
+	export GIT_VALGRIND
+fi
 GIT_TEMPLATE_DIR=$(pwd)/../templates/blt
 unset GIT_CONFIG
 GIT_CONFIG_NOSYSTEM=1
diff --git a/t/valgrind/.gitignore b/t/valgrind/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..d4ae6676d159599468de235bcf10a672cb452592
--- /dev/null
+++ b/t/valgrind/.gitignore
@@ -0,0 +1,2 @@
+/bin/
+/templates
diff --git a/t/valgrind/analyze.sh b/t/valgrind/analyze.sh
new file mode 100755
index 0000000000000000000000000000000000000000..d8105d9fabc3d0b0cb818d8c5504832f63c96b3e
--- /dev/null
+++ b/t/valgrind/analyze.sh
@@ -0,0 +1,123 @@
+#!/bin/sh
+
+out_prefix=$(dirname "$0")/../test-results/valgrind.out
+output=
+count=0
+total_count=0
+missing_message=
+new_line='
+'
+
+# start outputting the current valgrind error in $out_prefix.++$count,
+# and the test case which failed in the corresponding .message file
+start_output () {
+	test -z "$output" || return
+
+	# progress
+	total_count=$(($total_count+1))
+	test -t 2 && printf "\rFound %d errors" $total_count >&2
+
+	count=$(($count+1))
+	output=$out_prefix.$count
+	: > $output
+
+	echo "*** $1 ***" > $output.message
+}
+
+finish_output () {
+	test ! -z "$output" || return
+	output=
+
+	# if a test case has more than one valgrind error, we need to
+	# copy the last .message file to the previous errors
+	test -z "$missing_message" || {
+		while test $missing_message -lt $count
+		do
+			cp $out_prefix.$count.message \
+				$out_prefix.$missing_message.message
+			missing_message=$(($missing_message+1))
+		done
+		missing_message=
+	}
+}
+
+# group the valgrind errors by backtrace
+output_all () {
+	last_line=
+	j=0
+	i=1
+	while test $i -le $count
+	do
+		# output <number> <backtrace-in-one-line>
+		echo "$i $(tr '\n' ' ' < $out_prefix.$i)"
+		i=$(($i+1))
+	done |
+	sort -t ' ' -k 2 | # order by <backtrace-in-one-line>
+	while read number line
+	do
+		# find duplicates, do not output backtrace twice
+		if test "$line" != "$last_line"
+		then
+			last_line=$line
+			j=$(($j+1))
+			printf "\nValgrind error $j:\n\n"
+			cat $out_prefix.$number
+			printf "\nfound in:\n"
+		fi
+		# print the test case where this came from
+		printf "\n"
+		cat $out_prefix.$number.message
+	done
+}
+
+handle_one () {
+	OLDIFS=$IFS
+	IFS="$new_line"
+	while read line
+	do
+		case "$line" in
+		# backtrace, possibly a new one
+		==[0-9]*)
+
+			# Does the current valgrind error have a message yet?
+			case "$output" in
+			*.message)
+				test -z "$missing_message" &&
+				missing_message=$count
+				output=
+			esac
+
+			start_output $(basename $1)
+			echo "$line" |
+			sed 's/==[0-9]*==/==valgrind==/' >> $output
+			;;
+		# end of backtrace
+		'}')
+			test -z "$output" || {
+				echo "$line" >> $output
+				test $output = ${output%.message} &&
+				output=$output.message
+			}
+			;;
+		# end of test case
+		'')
+			finish_output
+			;;
+		# normal line; if $output is set, print the line
+		*)
+			test -z "$output" || echo "$line" >> $output
+			;;
+		esac
+	done < $1
+	IFS=$OLDIFS
+
+	# just to be safe
+	finish_output
+}
+
+for test_script in "$(dirname "$0")"/../test-results/*.out
+do
+	handle_one $test_script
+done
+
+output_all
diff --git a/t/valgrind/default.supp b/t/valgrind/default.supp
new file mode 100644
index 0000000000000000000000000000000000000000..9e013fa3b25b82a10b71ceabfa664c796c4d7a3f
--- /dev/null
+++ b/t/valgrind/default.supp
@@ -0,0 +1,45 @@
+{
+	ignore-zlib-errors-cond
+	Memcheck:Cond
+	obj:*libz.so*
+}
+
+{
+	ignore-zlib-errors-value8
+	Memcheck:Value8
+	obj:*libz.so*
+}
+
+{
+	ignore-zlib-errors-value4
+	Memcheck:Value4
+	obj:*libz.so*
+}
+
+{
+	ignore-ldso-cond
+	Memcheck:Cond
+	obj:*ld-*.so
+}
+
+{
+	ignore-ldso-addr8
+	Memcheck:Addr8
+	obj:*ld-*.so
+}
+
+{
+	ignore-ldso-addr4
+	Memcheck:Addr4
+	obj:*ld-*.so
+}
+
+{
+	writing-data-from-zlib-triggers-even-more-errors
+	Memcheck:Param
+	write(buf)
+	obj:/lib/ld-*.so
+	fun:write_in_full
+	fun:write_buffer
+	fun:write_loose_object
+}
diff --git a/t/valgrind/valgrind.sh b/t/valgrind/valgrind.sh
new file mode 100755
index 0000000000000000000000000000000000000000..582b4dca9497363c7bfd6ae5ecc2c98d28d5ac0a
--- /dev/null
+++ b/t/valgrind/valgrind.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+base=$(basename "$0")
+
+TRACK_ORIGINS=
+
+VALGRIND_VERSION=$(valgrind --version)
+VALGRIND_MAJOR=$(expr "$VALGRIND_VERSION" : '[^0-9]*\([0-9]*\)')
+VALGRIND_MINOR=$(expr "$VALGRIND_VERSION" : '[^0-9]*[0-9]*\.\([0-9]*\)')
+test 3 -gt "$VALGRIND_MAJOR" ||
+test 3 -eq "$VALGRIND_MAJOR" -a 4 -gt "$VALGRIND_MINOR" ||
+TRACK_ORIGINS=--track-origins=yes
+
+exec valgrind -q --error-exitcode=126 \
+	--leak-check=no \
+	--suppressions="$GIT_VALGRIND/default.supp" \
+	--gen-suppressions=all \
+	$TRACK_ORIGINS \
+	--log-fd=4 \
+	--input-fd=4 \
+	$GIT_VALGRIND_OPTIONS \
+	"$GIT_VALGRIND"/../../"$base" "$@"