diff --git a/index.js b/index.js
index a3a1aac..b30e58d 100644
--- a/index.js
+++ b/index.js
@@ -19,14 +19,15 @@ const NOASSERTION = 'NOASSERTION'
  *
  * @param {string} expression SPDX expression
  * @param {Function} licenseVisitor Optional. Bring your own visitor to clean each node
+ * @param {Function} licenseRefLookup Optional. Bring your own lookup to scan licenseRef
  * @returns {object} the AST representing the parsed expression
  */
-function parse(expression, licenseVisitor) {
+function parse(expression, licenseVisitor, licenseRefLookup) {
   // if the expression is already an expression, just return it.
   if (!(typeof expression === 'string')) return expression
   licenseVisitor = licenseVisitor || normalizeSingle
   try {
-    return spdxExpressionParse(expression, { relaxed: true, licenseVisitor })
+    return spdxExpressionParse(expression, { relaxed: true, licenseVisitor, licenseRefLookup })
   } catch (e) {
     return { noassertion: true }
   }
diff --git a/package-lock.json b/package-lock.json
index 483f543..18b9c2f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,16 +1,16 @@
 {
   "name": "@clearlydefined/spdx",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@clearlydefined/spdx",
-      "version": "0.1.8",
+      "version": "0.1.9",
       "license": "MIT",
       "dependencies": {
         "spdx-expression-parse": "github:clearlydefined/spdx-expression-parse.js#fork",
-        "spdx-license-ids": "^3.0.18",
+        "spdx-license-ids": "^3.0.20",
         "spdx-license-list": "^6.9.0",
         "spdx-satisfies": "github:clearlydefined/spdx-satisfies.js#parse-override"
       },
@@ -3214,9 +3214,9 @@
       }
     },
     "node_modules/spdx-license-ids": {
-      "version": "3.0.18",
-      "resolved": "https://registry.npmjs.org/spdx-license-ids/-/spdx-license-ids-3.0.18.tgz",
-      "integrity": "sha512-xxRs31BqRYHwiMzudOrpSiHtZ8i/GeionCBDSilhYRj+9gIcI8wCZTlXZKu9vZIVqViP3dcp9qE5G6AlIaD+TQ=="
+      "version": "3.0.20",
+      "resolved": "https://registry.npmjs.org/spdx-license-ids/-/spdx-license-ids-3.0.20.tgz",
+      "integrity": "sha512-jg25NiDV/1fLtSgEgyvVyDunvaNHbuwF9lfNV17gSmPFAlYzdfNBlLtLzXTevwkPj7DhGbmN9VnmJIgLnhvaBw=="
     },
     "node_modules/spdx-license-list": {
       "version": "6.9.0",
diff --git a/package.json b/package.json
index 8d55054..7919a78 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@clearlydefined/spdx",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "description": "SPDX custom libraries of clearlydefined.io.",
   "license": "MIT",
   "repository": {
@@ -20,7 +20,7 @@
   },
   "dependencies": {
     "spdx-expression-parse": "github:clearlydefined/spdx-expression-parse.js#fork",
-    "spdx-license-ids": "^3.0.18",
+    "spdx-license-ids": "^3.0.20",
     "spdx-license-list": "^6.9.0",
     "spdx-satisfies": "github:clearlydefined/spdx-satisfies.js#parse-override"
   },
diff --git a/test.js b/test.js
index 9c283d7..a79a7f0 100644
--- a/test.js
+++ b/test.js
@@ -98,6 +98,129 @@ describe('SPDX utility functions', () => {
     })
   })
 
+  it('parses licenseRef with lookup', () => {
+    const data = new Map([
+      ['afpl-9.0', { license: 'LicenseRef-scancode-afpl-9.0' }],
+      ['(afpl-9.0)', { license: 'LicenseRef-scancode-afpl-9.0' }],
+      [
+        '(afpl-9.0 OR Apache-2.0)',
+        {
+          left: { license: 'LicenseRef-scancode-afpl-9.0' },
+          conjunction: 'or',
+          right: { license: 'Apache-2.0' }
+        }
+      ],
+      [
+        'Apache-2.0 AND (afpl-9.0)',
+        {
+          left: { license: 'Apache-2.0' },
+          conjunction: 'and',
+          right: { license: 'LicenseRef-scancode-afpl-9.0' }
+        }
+      ],
+      [
+        'Apache-2.0 AND (afpl-9.0 AND afpl-9.0)',
+        {
+          left: { license: 'Apache-2.0' },
+          conjunction: 'and',
+          right: {
+            left: { license: 'LicenseRef-scancode-afpl-9.0' },
+            conjunction: 'and',
+            right: { license: 'LicenseRef-scancode-afpl-9.0' }
+          }
+        }
+      ],
+      [
+        '(afpl-9.0 AND afpl-9.0) AND Apache-2.0',
+        {
+          right: { license: 'Apache-2.0' },
+          conjunction: 'and',
+          left: {
+            left: { license: 'LicenseRef-scancode-afpl-9.0' },
+            conjunction: 'and',
+            right: { license: 'LicenseRef-scancode-afpl-9.0' }
+          }
+        }
+      ],
+      [
+        'Apache-2.0 AND (afpl-9.0 OR afpl-9.0)',
+        {
+          left: { license: 'Apache-2.0' },
+          conjunction: 'and',
+          right: {
+            left: { license: 'LicenseRef-scancode-afpl-9.0' },
+            conjunction: 'or',
+            right: { license: 'LicenseRef-scancode-afpl-9.0' }
+          }
+        }
+      ],
+      [
+        'MIT AND GPL-3.0',
+        {
+          left: { license: 'MIT' },
+          conjunction: 'and',
+          right: { license: 'GPL-3.0' }
+        }
+      ],
+      [
+        'AFL-1.1 AND afpl-9.0',
+        {
+          left: { license: 'AFL-1.1' },
+          conjunction: 'and',
+          right: { license: 'LicenseRef-scancode-afpl-9.0' }
+        }
+      ],
+      [
+        'afpl-9.0 AND MIT',
+        {
+          left: { license: 'LicenseRef-scancode-afpl-9.0' },
+          conjunction: 'and',
+          right: { license: 'MIT' }
+        }
+      ],
+      [
+        'afpl-9.0 AND activestate-community',
+        {
+          left: { license: 'LicenseRef-scancode-afpl-9.0' },
+          conjunction: 'and',
+          right: { license: 'LicenseRef-scancode-activestate-community' }
+        }
+      ],
+      [
+        'afpl-9.0 AND activestate-community OR ac3filter',
+        {
+          left: {
+            left: { license: 'LicenseRef-scancode-afpl-9.0' },
+            conjunction: 'and',
+            right: { license: 'LicenseRef-scancode-activestate-community' }
+          },
+          conjunction: 'or',
+          right: { license: 'LicenseRef-scancode-ac3filter' }
+        }
+      ],
+      ['INVALID', { noassertion: null }],
+      [
+        'LicenseRef-scancode-afpl-9.0 AND MIT',
+        {
+          left: { license: 'LicenseRef-scancode-afpl-9.0' },
+          conjunction: 'and',
+          right: { license: 'MIT' }
+        }
+      ]
+    ])
+
+    const licenseRefLookup = function (identifier) {
+      if (identifier === 'afpl-9.0') return 'LicenseRef-scancode-afpl-9.0'
+      if (identifier === 'activestate-community') return 'LicenseRef-scancode-activestate-community'
+      if (identifier === 'ac3filter') return 'LicenseRef-scancode-ac3filter'
+      return identifier
+    }
+
+    data.forEach((expected, input) => {
+      expect(SPDX.parse(input, undefined, licenseRefLookup)).to.deep.equal(expected)
+    })
+  })
+
   it('stringifies spdx objects', () => {
     const data = new Map([
       [{ license: 'MIT' }, 'MIT'],