diff --git a/object.c b/object.c
index 23d6c96719..980ac5fcdf 100644
--- a/object.c
+++ b/object.c
@@ -41,7 +41,8 @@ int type_from_string_gently(const char *str, ssize_t len, int gentle)
 		len = strlen(str);
 
 	for (i = 1; i < ARRAY_SIZE(object_type_strings); i++)
-		if (!strncmp(str, object_type_strings[i], len))
+		if (!strncmp(str, object_type_strings[i], len) &&
+		    object_type_strings[i][len] == '\0')
 			return i;
 
 	if (gentle)
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index f83df8eb8b..ebb3a69c8c 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -201,4 +201,12 @@ test_expect_success 'corrupt tag' '
 	test_must_fail git hash-object -t tag --stdin </dev/null
 '
 
+test_expect_success 'hash-object complains about bogus type name' '
+	test_must_fail git hash-object -t bogus --stdin </dev/null
+'
+
+test_expect_success 'hash-object complains about truncated type name' '
+	test_must_fail git hash-object -t bl --stdin </dev/null
+'
+
 test_done