diff --git a/.gitignore b/.gitignore
index 5054208..de82825 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 dist/
 testpages/*
 tests/test_results.txt
+robots.html
diff --git a/selector.go b/selector.go
index 75d4307..694f028 100644
--- a/selector.go
+++ b/selector.go
@@ -378,6 +378,14 @@ func ParsePseudo(selector *CSSSelector, s scanner.Scanner) error {
 		if selector.Pseudo, err = parseNthPseudo(cmd); err != nil {
 			return err
 		}
+	case strings.HasPrefix(cmd, "not("):
+		if selector.Pseudo, err = parseNotPseudo(cmd[len("not("):]); err != nil {
+			return err
+		}
+	case strings.HasPrefix(cmd, "parent-of("):
+		if selector.Pseudo, err = parseParentOfPseudo(cmd[len("parent-of("):]); err != nil {
+			return err
+		}
 	default:
 		return fmt.Errorf("%s not a valid pseudo class", cmd)
 	}
@@ -583,3 +591,54 @@ func parseContainsPseudo(cmd string) (PseudoClass, error) {
 		}
 	}
 }
+
+// Parse a :not(selector) selector
+// expects the input to be everything after the open parenthesis
+// e.g. for `not(div#id)` the argument would be `div#id)`
+func parseNotPseudo(cmd string) (PseudoClass, error) {
+	if len(cmd) < 2 {
+		return nil, fmt.Errorf("malformed ':not' selector")
+	}
+	endQuote, cmd := cmd[len(cmd)-1], cmd[:len(cmd)-1]
+	selector, err := ParseSelector(cmd)
+	if err != nil {
+		return nil, err
+	}
+	if selector.Pseudo != nil {
+		return nil, fmt.Errorf("selector within ':not' may not contain a pseudo class")
+	}
+	if endQuote != ')' {
+		return nil, fmt.Errorf("unmatched '('")
+	}
+	return func(n *html.Node) bool {
+		return !selector.Match(n)
+	}, nil
+}
+
+// Parse a :parent-of(selector) selector
+// expects the input to be everything after the open parenthesis
+// e.g. for `parent-of(div#id)` the argument would be `div#id)`
+func parseParentOfPseudo(cmd string) (PseudoClass, error) {
+	if len(cmd) < 2 {
+		return nil, fmt.Errorf("malformed ':parent-of' selector")
+	}
+	endQuote, cmd := cmd[len(cmd)-1], cmd[:len(cmd)-1]
+	selector, err := ParseSelector(cmd)
+	if err != nil {
+		return nil, err
+	}
+	if selector.Pseudo != nil {
+		return nil, fmt.Errorf("selector within ':parent-of' may not contain a pseudo class")
+	}
+	if endQuote != ')' {
+		return nil, fmt.Errorf("unmatched '('")
+	}
+	return func(n *html.Node) bool {
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			if c.Type == html.ElementNode && selector.Match(c) {
+				return true
+			}
+		}
+		return false
+	}, nil
+}
diff --git a/tests/cmds.txt b/tests/cmds.txt
index 56c192d..b05f947 100644
--- a/tests/cmds.txt
+++ b/tests/cmds.txt
@@ -38,3 +38,4 @@ td:empty
 #toc li + a + span
 #toc li + span
 #toc li > li
+li a:not([rel])
diff --git a/tests/expected_output.txt b/tests/expected_output.txt
index db4cd5f..4f5dec8 100644
--- a/tests/expected_output.txt
+++ b/tests/expected_output.txt
@@ -38,3 +38,4 @@ dbc580de40eeb8448f0dbe1b98d74cf799a6868b #toc li + a
 0cd687baaf08605bf6a68e3c285c5e8a41e0c9b2 #toc li + a + span
 da39a3ee5e6b4b0d3255bfef95601890afd80709 #toc li + span
 5d6e3ed3cfe310cde185cbfe1bba6aa7ec2a7f8d #toc li > li
+87eee1189dd5296d6c010a1ad329fc53c6099d72 li a:not([rel])