diff --git a/lib/less/parser.js b/lib/less/parser.js
index b7cbde4..67a6cac 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -227,7 +227,11 @@ less.Parser = function Parser(env) {
                                 chunks[++j] = [];
                             } else {
                                 if (c === '"' || c === "'") {
-                                    inString = inString === c ? false : c;
+                                    if (!inString) {
+                                        inString = c;
+                                    } else {
+                                        inString = inString === c ? false : inString;
+                                    }
                                 }
                                 chunk.push(c);
                             }