diff --git a/src/parse.spec.ts b/src/parse.spec.ts
index e5577a9e..02ddb55e 100644
--- a/src/parse.spec.ts
+++ b/src/parse.spec.ts
@@ -38,6 +38,7 @@ const broken = [
     ":has(p",
     ":foo(p()",
     "#",
+    "##foo",
 ];
 
 describe("Broken selectors", () => {
diff --git a/src/parse.ts b/src/parse.ts
index 86f71095..677a029d 100644
--- a/src/parse.ts
+++ b/src/parse.ts
@@ -78,7 +78,7 @@ export type TraversalType =
     | "parent"
     | "sibling";
 
-const reName = /^[^\\]?(?:\\(?:[\da-f]{1,6}\s?|.)|[\w\-\u00b0-\uFFFF])+/;
+const reName = /^[^\\#]?(?:\\(?:[\da-f]{1,6}\s?|.)|[\w\-\u00b0-\uFFFF])+/;
 const reEscape = /\\([\da-f]{1,6}\s?|(\s)|.)/gi;
 // Modified version of https://github.com/jquery/sizzle/blob/master/src/sizzle.js#L87
 const reAttr = /^\s*(?:(\*|[-\w]*)\|)?((?:\\.|[\w\u00b0-\uFFFF-])+)\s*(?:(\S?)=\s*(?:(['"])((?:[^\\]|\\[^])*?)\4|(#?(?:\\.|[\w\u00b0-\uFFFF-])*)|)|)\s*([iI])?\]/;