diff --git a/sjson.go b/sjson.go
index 8213e49..69c40b7 100644
--- a/sjson.go
+++ b/sjson.go
@@ -110,7 +110,7 @@ func parsePath(path string) (pathResult, error) {
 
 func mustMarshalString(s string) bool {
 	for i := 0; i < len(s); i++ {
-		if s[i] < ' ' || s[i] > 0x7f || s[i] == '"' {
+		if s[i] < ' ' || s[i] > 0x7f || s[i] == '"' || (s[i] == '\\' && i == len(s)-1) {
 			return true
 		}
 	}
diff --git a/sjson_test.go b/sjson_test.go
index e9f0df0..75f1c4d 100644
--- a/sjson_test.go
+++ b/sjson_test.go
@@ -139,6 +139,7 @@ func TestBasic(t *testing.T) {
 	testRaw(t, setBool, `[true]`, ``, `0`, true)
 	testRaw(t, setBool, `[null]`, ``, `0`, nil)
 	testRaw(t, setString, `{"arr":[1]}`, ``, `arr.-1`, 1)
+	testRaw(t, setString, `{"a":"\\"}`, ``, `a`, "\\")
 }
 
 func TestDelete(t *testing.T) {