diff --git a/src/gen/api/accountingApi.ts b/src/gen/api/accountingApi.ts
index c7503937c..29d15bda1 100644
--- a/src/gen/api/accountingApi.ts
+++ b/src/gen/api/accountingApi.ts
@@ -2142,9 +2142,10 @@ export class AccountingApi {
      * @param idempotencyKey This allows you to safely retry requests without the risk of duplicate processing. 128 character max.
      */     
     public async createInvoiceAttachmentByFileName (xeroTenantId: string, invoiceID: string, fileName: string, body: fs.ReadStream | Readable | Buffer , includeOnline?: boolean, idempotencyKey?: string, options: {headers: {[name: string]: string}} = {headers: {}}) : Promise<{ response: AxiosResponse; body: Attachments;  }> {
+        const normalizedFileName = String(fileName).trimEnd();
         const localVarPath = this.basePath + '/Invoices/{InvoiceID}/Attachments/{FileName}'
             .replace('{' + 'InvoiceID' + '}', encodeURIComponent(String(invoiceID)))
-            .replace('{' + 'FileName' + '}', encodeURIComponent(String(fileName)));
+            .replace('{' + 'FileName' + '}', encodeURIComponent(normalizedFileName));
         let localVarQueryParameters: any = {};
         let localVarHeaderParams: any = (<any>Object).assign({}, this.defaultHeaders);
         let localVarFormParams: any = {};
@@ -17337,9 +17338,10 @@ export class AccountingApi {
      * @param idempotencyKey This allows you to safely retry requests without the risk of duplicate processing. 128 character max.
      */     
     public async updateInvoiceAttachmentByFileName (xeroTenantId: string, invoiceID: string, fileName: string, body: fs.ReadStream | Readable | Buffer , idempotencyKey?: string, options: {headers: {[name: string]: string}} = {headers: {}}) : Promise<{ response: AxiosResponse; body: Attachments;  }> {
+        const normalizedFileName = String(fileName).trimEnd();
         const localVarPath = this.basePath + '/Invoices/{InvoiceID}/Attachments/{FileName}'
             .replace('{' + 'InvoiceID' + '}', encodeURIComponent(String(invoiceID)))
-            .replace('{' + 'FileName' + '}', encodeURIComponent(String(fileName)));
+            .replace('{' + 'FileName' + '}', encodeURIComponent(normalizedFileName));
         let localVarQueryParameters: any = {};
         let localVarHeaderParams: any = (<any>Object).assign({}, this.defaultHeaders);
         let localVarFormParams: any = {};
diff --git a/src/test/accountingApi.spec.ts b/src/test/accountingApi.spec.ts
new file mode 100644
index 000000000..a9ddf1414
--- /dev/null
+++ b/src/test/accountingApi.spec.ts
@@ -0,0 +1,48 @@
+jest.mock('axios', () => jest.fn());
+
+import axios from 'axios';
+import { AccountingApi } from '../gen/api/accountingApi';
+
+describe('AccountingApi invoice attachment filenames', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    (axios as unknown as jest.Mock).mockResolvedValue({
+      status: 200,
+      data: {},
+    });
+  });
+
+  it('trims trailing spaces when creating an invoice attachment by filename', async () => {
+    const api = new AccountingApi();
+
+    await api.createInvoiceAttachmentByFileName(
+      'tenant-123',
+      'invoice-123',
+      'invoice copy.pdf   ',
+      Buffer.from('hello'),
+    );
+
+    expect(axios).toHaveBeenCalledWith(
+      expect.objectContaining({
+        url: 'https://api.xero.com/api.xro/2.0/Invoices/invoice-123/Attachments/invoice%20copy.pdf',
+      }),
+    );
+  });
+
+  it('trims trailing spaces when updating an invoice attachment by filename', async () => {
+    const api = new AccountingApi();
+
+    await api.updateInvoiceAttachmentByFileName(
+      'tenant-123',
+      'invoice-123',
+      'invoice copy.pdf   ',
+      Buffer.from('hello'),
+    );
+
+    expect(axios).toHaveBeenCalledWith(
+      expect.objectContaining({
+        url: 'https://api.xero.com/api.xro/2.0/Invoices/invoice-123/Attachments/invoice%20copy.pdf',
+      }),
+    );
+  });
+});