diff --git a/t/t5547-push-quarantine.sh b/t/t5547-push-quarantine.sh
index 1e5d32d068..6275ec807b 100755
--- a/t/t5547-push-quarantine.sh
+++ b/t/t5547-push-quarantine.sh
@@ -33,4 +33,23 @@ test_expect_success 'rejected objects are removed' '
 	test_cmp expect actual
 '
 
+# MINGW does not allow colons in pathnames in the first place
+test_expect_success !MINGW 'push to repo path with colon' '
+	# The interesting failure case here is when the
+	# receiving end cannot access its original object directory,
+	# so make it likely for us to generate a delta by having
+	# a non-trivial file with multiple versions.
+
+	test-genrandom foo 4096 >file.bin &&
+	git add file.bin &&
+	git commit -m bin &&
+	git clone --bare . xxx:yyy.git &&
+
+	echo change >>file.bin &&
+	git commit -am change &&
+	# Note that we have to use the full path here, or it gets confused
+	# with the ssh host:path syntax.
+	git push "$PWD/xxx:yyy.git" HEAD
+'
+
 test_done
diff --git a/tmp-objdir.c b/tmp-objdir.c
index 64435f23a4..b2d9280f10 100644
--- a/tmp-objdir.c
+++ b/tmp-objdir.c
@@ -5,6 +5,7 @@
 #include "string-list.h"
 #include "strbuf.h"
 #include "argv-array.h"
+#include "quote.h"
 
 struct tmp_objdir {
 	struct strbuf path;
@@ -79,12 +80,27 @@ static void remove_tmp_objdir_on_signal(int signo)
  */
 static void env_append(struct argv_array *env, const char *key, const char *val)
 {
-	const char *old = getenv(key);
+	struct strbuf quoted = STRBUF_INIT;
+	const char *old;
 
+	/*
+	 * Avoid quoting if it's not necessary, for maximum compatibility
+	 * with older parsers which don't understand the quoting.
+	 */
+	if (*val == '"' || strchr(val, PATH_SEP)) {
+		strbuf_addch(&quoted, '"');
+		quote_c_style(val, &quoted, NULL, 1);
+		strbuf_addch(&quoted, '"');
+		val = quoted.buf;
+	}
+
+	old = getenv(key);
 	if (!old)
 		argv_array_pushf(env, "%s=%s", key, val);
 	else
 		argv_array_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
+
+	strbuf_release(&quoted);
 }
 
 static void env_replace(struct argv_array *env, const char *key, const char *val)