diff --git a/README.md b/README.md
index f7c58ed3..132daa1f 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,13 @@ joinURL('a', '/b', '/c')
 joinURL('http://foo.com/foo?test=123#token', 'bar', 'baz')
 ```
 
+### `withparams`
+
+```ts
+// Result: /foo?page=a&token=secret
+withParams('/foo?page=a', { token: 'secret' })
+```
+
 ### `withTrailingSlash`
 
 Ensures url ends with a trailing slash
diff --git a/src/index.ts b/src/index.ts
index b75094cb..80133cc9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -6,6 +6,8 @@ export interface ParsedURL {
 
 export type InputURL = string | ParsedURL
 
+export type URLParams = { [key: string]: any }
+
 export function withoutTrailingSlash (input: string = ''): string {
   return input.endsWith('/') ? input.slice(0, -1) : input
 }
@@ -50,6 +52,14 @@ export function normalizeURL (input: InputURL, stripBase?: boolean): string {
   return isRelative ? path.substr(1) : path
 }
 
+export function withParams (input: InputURL, params: URLParams): string {
+  const parsed = parseURL(input)
+  for (const name in params) {
+    parsed.url.searchParams.set(name, params[name])
+  }
+  return normalizeURL(parsed)
+}
+
 export function joinURL (input0: string, ...input: string[]): string {
   const path = input.map(parseURL)
   const baseURL = parseURL(input0)
diff --git a/test/params.test.ts b/test/params.test.ts
new file mode 100644
index 00000000..969c1644
--- /dev/null
+++ b/test/params.test.ts
@@ -0,0 +1,19 @@
+// @ts-nocheck
+import { withParams } from '../src'
+
+describe('withParams', () => {
+  const tests = [
+    { input: '', params: {}, out: '' },
+    { input: '/', params: {}, out: '/' },
+    { input: '?test', params: {}, out: '?test' },
+    { input: '/?test', params: {}, out: '/?test' },
+    { input: '/?test', params: { foo: 1 }, out: '/?test=&foo=1' },
+    { input: '/?foo=1', params: { foo: 2 }, out: '/?foo=2' }
+  ]
+
+  for (const t of tests) {
+    test(t.input.toString() + ' with ' + JSON.stringify(t.params), () => {
+      expect(withParams(t.input, t.params)).toBe(t.out)
+    })
+  }
+})