diff --git a/src/middlewares/openapi.request.validator.ts b/src/middlewares/openapi.request.validator.ts
index 8a3cf607..2060f534 100644
--- a/src/middlewares/openapi.request.validator.ts
+++ b/src/middlewares/openapi.request.validator.ts
@@ -164,8 +164,16 @@ export class RequestValidator {
     };
   }
 
-  private processQueryParam(query, schema, whiteList: string[] = []) {
-    const keys = schema.properties ? Object.keys(schema.properties) : [];
+  private processQueryParam(query: object, schema, whiteList: string[] = []) {
+    const entries = Object.entries(schema.properties ?? {});
+    let keys = [];
+    for (const [key, prop] of entries) {
+      if (prop['type'] === 'object' && prop['additionalProperties']) {
+        // we have an object that allows additional properties
+        return;
+      }
+      keys.push(key);
+    }
     const knownQueryParams = new Set(keys);
     whiteList.forEach((item) => knownQueryParams.add(item));
     const queryParams = Object.keys(query);
diff --git a/test/additional.props.query.params.spec.ts b/test/additional.props.query.params.spec.ts
new file mode 100644
index 00000000..0e5b662e
--- /dev/null
+++ b/test/additional.props.query.params.spec.ts
@@ -0,0 +1,47 @@
+import * as path from 'path';
+import * as express from 'express';
+import * as request from 'supertest';
+import { createApp } from './common/app';
+import * as packageJson from '../package.json';
+import { expect } from 'chai';
+
+describe(packageJson.name, () => {
+  let app = null;
+
+  before(async () => {
+    // Set up the express app
+    const apiSpec = path.join(
+      'test',
+      'resources',
+      'additional.props.query.params.yaml',
+    );
+    app = await createApp({ apiSpec }, 3005, (app) =>
+      app.use(
+        express
+          .Router()
+          .get(`/params_with_additional_props`, (req, res) =>
+            res.status(200).json(req.body),
+          ),
+      ),
+    );
+  });
+
+  after(() => {
+    app.server.close();
+  });
+
+  it('should allow additional / unknown properties properties', async () =>
+    request(app)
+      .get(`/params_with_additional_props`)
+      .query({ required: 1, test: 'test' })
+      .expect(200));
+
+  it('should return 400 on missing required prop (when using additional props explode object)', async () =>
+    request(app)
+      .get(`/params_with_additional_props`)
+      .query({ test: 'test' })
+      .expect(400)
+      .then((r) => {
+        expect(r.body.message).to.contain('required');
+      }));
+});
diff --git a/test/resources/additional.props.query.params.yaml b/test/resources/additional.props.query.params.yaml
new file mode 100644
index 00000000..b75d7cd7
--- /dev/null
+++ b/test/resources/additional.props.query.params.yaml
@@ -0,0 +1,41 @@
+openapi: 3.0.3
+info:
+  version: 1.0.0
+  title: Test
+  description: A sample API
+servers:
+  - url: /
+paths:
+  /params_with_additional_props:
+    get:
+      parameters:
+        - name: required
+          in: query
+          description: maximum number of results to return
+          required: true
+          schema:
+            type: integer
+            format: int32
+            minimum: 1
+            maximum: 20
+        - name: params
+          in: query
+          required: false
+          schema:
+            type: object
+            # If the parameter values are of specific type, e.g. string:
+            # additionalProperties:
+            #   type: string
+            # If the parameter values can be of different types
+            # (e.g. string, number, boolean, ...)
+            additionalProperties: true
+
+          # `style: form` and `explode: true` is the default serialization method
+          # for query parameters, so these keywords can be omitted
+          style: form
+          explode: true
+      responses:
+        '200':
+          description: the response
+
+