diff --git a/packages/block-editor/src/utils/transform-styles/ast/parse.js b/packages/block-editor/src/utils/transform-styles/ast/parse.js
index d3746488fc1fe2..270a25fd989a0c 100644
--- a/packages/block-editor/src/utils/transform-styles/ast/parse.js
+++ b/packages/block-editor/src/utils/transform-styles/ast/parse.js
@@ -254,7 +254,7 @@ export default function( css, options ) {
 
 		// val
 		const val = match(
-			/^((?:'(?:\\'|.)*?'|"(?:\\"|.)*?"|\([^\)]*?\)|[^};])+)/
+			/^((?:\/\*.*?\*\/|'(?:\\'|.)*?'|"(?:\\"|.)*?"|\((\s*'(?:\\'|.)*?'|"(?:\\"|.)*?"|[^)]*?)\s*\)|[^};])+)/
 		);
 
 		const ret = pos( {
diff --git a/packages/block-editor/src/utils/transform-styles/test/__snapshots__/index.js.snap b/packages/block-editor/src/utils/transform-styles/test/__snapshots__/index.js.snap
new file mode 100644
index 00000000000000..f908d3cf289615
--- /dev/null
+++ b/packages/block-editor/src/utils/transform-styles/test/__snapshots__/index.js.snap
@@ -0,0 +1,133 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`CSS parse Should handle closing parenthesis within url 1`] = `
+Object {
+  "stylesheet": Object {
+    "parsingErrors": Array [],
+    "rules": Array [
+      Object {
+        "declarations": Array [
+          Object {
+            "position": Position {
+              "end": Object {
+                "column": 17,
+                "line": 1,
+              },
+              "source": undefined,
+              "start": Object {
+                "column": 6,
+                "line": 1,
+              },
+            },
+            "property": "b",
+            "type": "declaration",
+            "value": "url(\\")\\")",
+          },
+          Object {
+            "position": Position {
+              "end": Object {
+                "column": 31,
+                "line": 1,
+              },
+              "source": undefined,
+              "start": Object {
+                "column": 19,
+                "line": 1,
+              },
+            },
+            "property": "d",
+            "type": "declaration",
+            "value": "url(\\";a\\")",
+          },
+        ],
+        "position": Position {
+          "end": Object {
+            "column": 34,
+            "line": 1,
+          },
+          "source": undefined,
+          "start": Object {
+            "column": 1,
+            "line": 1,
+          },
+        },
+        "selectors": Array [
+          ".a",
+        ],
+        "type": "rule",
+      },
+    ],
+    "source": undefined,
+  },
+  "type": "stylesheet",
+}
+`;
+
+exports[`CSS parse Should handle urls without quotes 1`] = `
+Object {
+  "stylesheet": Object {
+    "parsingErrors": Array [],
+    "rules": Array [
+      Object {
+        "declarations": Array [
+          Object {
+            "position": Position {
+              "end": Object {
+                "column": 217,
+                "line": 2,
+              },
+              "source": undefined,
+              "start": Object {
+                "column": 4,
+                "line": 2,
+              },
+            },
+            "property": "background-image",
+            "type": "declaration",
+            "value": "url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAQAAAAEBAMAAABb34NNAAAAFVBMVEXyrmHqcBDtdQ3pcRHcbRkAAAD/uSmYi/+cAAAABnRSTlORbFE2DwAwkbURAAAAEUlEQVQI12MIEmEwSwAiIAMAC/AB+fq6WIgAAAAASUVORK5CYII=)",
+          },
+          Object {
+            "position": Position {
+              "end": Object {
+                "column": 3,
+                "line": 4,
+              },
+              "source": undefined,
+              "start": Object {
+                "column": 4,
+                "line": 3,
+              },
+            },
+            "property": "background-repeat",
+            "type": "declaration",
+            "value": "no-repeat",
+          },
+        ],
+        "position": Position {
+          "end": Object {
+            "column": 4,
+            "line": 4,
+          },
+          "source": undefined,
+          "start": Object {
+            "column": 1,
+            "line": 1,
+          },
+        },
+        "selectors": Array [
+          ".a",
+        ],
+        "type": "rule",
+      },
+    ],
+    "source": undefined,
+  },
+  "type": "stylesheet",
+}
+`;
+
+exports[`CSS traverse Should traverse the CSS 1`] = `
+"namespace h1 {
+color: red;
+}"
+`;
diff --git a/packages/block-editor/src/utils/transform-styles/test/__snapshots__/traverse.js.snap b/packages/block-editor/src/utils/transform-styles/test/__snapshots__/traverse.js.snap
deleted file mode 100644
index 1ff3cab7d63365..00000000000000
--- a/packages/block-editor/src/utils/transform-styles/test/__snapshots__/traverse.js.snap
+++ /dev/null
@@ -1,7 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`CSS traverse Should traverse the CSS 1`] = `
-"namespace h1 {
-color: red;
-}"
-`;
diff --git a/packages/block-editor/src/utils/transform-styles/test/index.js b/packages/block-editor/src/utils/transform-styles/test/index.js
new file mode 100644
index 00000000000000..61c7a290ec02f5
--- /dev/null
+++ b/packages/block-editor/src/utils/transform-styles/test/index.js
@@ -0,0 +1,44 @@
+/**
+ * Internal dependencies
+ */
+import traverse from '../traverse';
+import parse from '../ast/parse';
+
+describe( 'CSS traverse', () => {
+	it( 'Should traverse the CSS', () => {
+		const input = `h1 { color: red; }`;
+		const output = traverse( input, ( node ) => {
+			if ( node.type === 'rule' ) {
+				return {
+					...node,
+					selectors: node.selectors.map(
+						( selector ) => 'namespace ' + selector
+					),
+				};
+			}
+
+			return node;
+		} );
+
+		expect( output ).toMatchSnapshot();
+	} );
+} );
+
+describe( 'CSS parse', () => {
+	it( 'Should handle closing parenthesis within url', () => {
+		const input = `.a { b: url(")"); d: url(";a"); }`;
+		const output = parse( input );
+
+		expect( output ).toMatchSnapshot();
+	} );
+
+	it( 'Should handle urls without quotes', () => {
+		const input = `.a {
+			background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAQAAAAEBAMAAABb34NNAAAAFVBMVEXyrmHqcBDtdQ3pcRHcbRkAAAD/uSmYi/+cAAAABnRSTlORbFE2DwAwkbURAAAAEUlEQVQI12MIEmEwSwAiIAMAC/AB+fq6WIgAAAAASUVORK5CYII=);
+			background-repeat: no-repeat
+		}`;
+		const output = parse( input );
+
+		expect( output ).toMatchSnapshot();
+	} );
+} );
diff --git a/packages/block-editor/src/utils/transform-styles/test/traverse.js b/packages/block-editor/src/utils/transform-styles/test/traverse.js
deleted file mode 100644
index bb1be2635fe535..00000000000000
--- a/packages/block-editor/src/utils/transform-styles/test/traverse.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/**
- * Internal dependencies
- */
-import traverse from '../traverse';
-
-describe( 'CSS traverse', () => {
-	it( 'Should traverse the CSS', () => {
-		const input = `h1 { color: red; }`;
-		const output = traverse( input, ( node ) => {
-			if ( node.type === 'rule' ) {
-				return {
-					...node,
-					selectors: node.selectors.map(
-						( selector ) => 'namespace ' + selector
-					),
-				};
-			}
-
-			return node;
-		} );
-
-		expect( output ).toMatchSnapshot();
-	} );
-} );