diff --git a/models/AccountingConnection.js b/models/AccountingConnection.js
new file mode 100644
index 0000000..b12aa46
--- /dev/null
+++ b/models/AccountingConnection.js
@@ -0,0 +1,14 @@
+const mongoose = require('mongoose');
+
+const accountingConnectionSchema = new mongoose.Schema({
+  user: { type: mongoose.Schema.Types.ObjectId, ref: 'User', required: true },
+  platform: { type: String, enum: ['quickbooks', 'xero'], required: true },
+  accessToken: { type: String, required: true },
+  refreshToken: { type: String, required: true },
+  realmId: { type: String }, // For QuickBooks company ID
+  tenantId: { type: String }, // For Xero tenant ID
+  expiresAt: { type: Date, required: true },
+  connectedAt: { type: Date, default: Date.now }
+});
+
+module.exports = mongoose.model('AccountingConnection', accountingConnectionSchema);
\ No newline at end of file
diff --git a/models/Expense.js b/models/Expense.js
index dde44ab..887dad0 100644
--- a/models/Expense.js
+++ b/models/Expense.js
@@ -73,16 +73,10 @@ const expenseSchema = new mongoose.Schema({
     type: Boolean,
     default: false
   },
-  status: {
-    type: String,
-    enum: ['draft', 'pending_approval', 'approved', 'rejected'],
-    default: 'approved' // Default to approved for backward compatibility
-  },
-  approvalWorkflow: {
-    type: mongoose.Schema.Types.ObjectId,
-    ref: 'ApprovalWorkflow'
+  syncedToAccounting: {
+    type: Boolean,
+    default: false
   }
-}, {
   timestamps: true
 });
 
diff --git a/package.json b/package.json
index c5e2b29..3984be2 100644
--- a/package.json
+++ b/package.json
@@ -28,7 +28,10 @@
     "simple-statistics": "^7.8.3",
     "node-fetch": "^3.3.2",
     "moment-timezone": "^0.5.43",
-    "i18next": "^23.7.6"
+    "i18next": "^23.7.6",
+    "i18next-fs-backend": "^2.3.1",
+    "intuit-oauth": "^4.0.0",
+    "xero-node": "^4.20.0"
   },
   "devDependencies": {
     "nodemon": "^3.0.1"
diff --git a/routes/accounting.js b/routes/accounting.js
new file mode 100644
index 0000000..571e82e
--- /dev/null
+++ b/routes/accounting.js
@@ -0,0 +1,86 @@
+const express = require('express');
+const router = express.Router();
+const accountingService = require('../services/accountingService');
+const auth = require('../middleware/auth');
+
+// Get auth URL for platform
+router.get('/auth/:platform', auth, async (req, res) => {
+  try {
+    const { platform } = req.params;
+    const userId = req.user.id;
+
+    let authUrl;
+    if (platform === 'quickbooks') {
+      authUrl = await accountingService.getQuickBooksAuthUrl(userId);
+    } else if (platform === 'xero') {
+      authUrl = await accountingService.getXeroAuthUrl(userId);
+    } else {
+      return res.status(400).json({ error: 'Unsupported platform' });
+    }
+
+    res.json({ authUrl });
+  } catch (error) {
+    console.error('Auth URL error:', error);
+    res.status(500).json({ error: 'Failed to generate auth URL' });
+  }
+});
+
+// Handle OAuth callback
+router.get('/callback/:platform', async (req, res) => {
+  try {
+    const { platform } = req.params;
+    const { code, state } = req.query;
+
+    let connection;
+    if (platform === 'quickbooks') {
+      connection = await accountingService.handleQuickBooksCallback(code, state);
+    } else if (platform === 'xero') {
+      connection = await accountingService.handleXeroCallback(code, state);
+    } else {
+      return res.status(400).json({ error: 'Unsupported platform' });
+    }
+
+    // Redirect to frontend with success
+    res.redirect(`${process.env.FRONTEND_URL}/settings/accounting?connected=${platform}`);
+  } catch (error) {
+    console.error('Callback error:', error);
+    res.redirect(`${process.env.FRONTEND_URL}/settings/accounting?error=${encodeURIComponent(error.message)}`);
+  }
+});
+
+// Get user's connected platforms
+router.get('/connections', auth, async (req, res) => {
+  try {
+    const connections = await accountingService.getUserConnections(req.user.id);
+    res.json(connections);
+  } catch (error) {
+    console.error('Get connections error:', error);
+    res.status(500).json({ error: 'Failed to get connections' });
+  }
+});
+
+// Sync expenses to platform
+router.post('/sync/:platform', auth, async (req, res) => {
+  try {
+    const { platform } = req.params;
+    const result = await accountingService.syncExpensesToAccounting(req.user.id, platform);
+    res.json(result);
+  } catch (error) {
+    console.error('Sync error:', error);
+    res.status(500).json({ error: error.message });
+  }
+});
+
+// Disconnect platform
+router.delete('/disconnect/:platform', auth, async (req, res) => {
+  try {
+    const { platform } = req.params;
+    await accountingService.disconnectPlatform(req.user.id, platform);
+    res.json({ message: 'Disconnected successfully' });
+  } catch (error) {
+    console.error('Disconnect error:', error);
+    res.status(500).json({ error: 'Failed to disconnect' });
+  }
+});
+
+module.exports = router;
\ No newline at end of file
diff --git a/server.js b/server.js
index 67e8a12..e59f143 100644
--- a/server.js
+++ b/server.js
@@ -227,6 +227,7 @@ app.use('/api/ai', require('./routes/ai'));
 app.use('/api/multicurrency', require('./routes/multicurrency'));
 app.use('/api/collaboration', require('./routes/collaboration'));
 app.use('/api/audit-compliance', require('./routes/auditCompliance'));
+app.use('/api/accounting', require('./routes/accounting'));
 app.use('/api/analytics', require('./routes/analytics'));
 app.use('/api/fraud-detection', require('./routes/fraudDetection'));
 
diff --git a/services/accountingService.js b/services/accountingService.js
new file mode 100644
index 0000000..e6dfd75
--- /dev/null
+++ b/services/accountingService.js
@@ -0,0 +1,210 @@
+const axios = require('axios');
+const OAuthClient = require('intuit-oauth');
+const { XeroClient } = require('xero-node');
+const AccountingConnection = require('../models/AccountingConnection');
+const Expense = require('../models/Expense');
+
+class AccountingService {
+  constructor() {
+    // QuickBooks OAuth client
+    this.qbClient = new OAuthClient({
+      clientId: process.env.QUICKBOOKS_CLIENT_ID,
+      clientSecret: process.env.QUICKBOOKS_CLIENT_SECRET,
+      redirectUri: process.env.QUICKBOOKS_REDIRECT_URI,
+      environment: process.env.NODE_ENV === 'production' ? 'production' : 'sandbox'
+    });
+
+    // Xero client
+    this.xeroClient = new XeroClient({
+      clientId: process.env.XERO_CLIENT_ID,
+      clientSecret: process.env.XERO_CLIENT_SECRET,
+      redirectUris: [process.env.XERO_REDIRECT_URI],
+      scopes: ['accounting.transactions', 'accounting.contacts']
+    });
+  }
+
+  // QuickBooks methods
+  async getQuickBooksAuthUrl(userId) {
+    const authUri = this.qbClient.authorizeUri({
+      scope: ['com.intuit.quickbooks.accounting'],
+      state: `user_${userId}`
+    });
+    return authUri;
+  }
+
+  async handleQuickBooksCallback(code, state) {
+    const userId = state.replace('user_', '');
+    const authResponse = await this.qbClient.createToken(code);
+    const tokenData = authResponse.getJson();
+
+    const connection = new AccountingConnection({
+      user: userId,
+      platform: 'quickbooks',
+      accessToken: tokenData.access_token,
+      refreshToken: tokenData.refresh_token,
+      realmId: tokenData.realmId,
+      expiresAt: new Date(Date.now() + tokenData.expires_in * 1000)
+    });
+
+    await connection.save();
+    return connection;
+  }
+
+  async refreshQuickBooksToken(connection) {
+    this.qbClient.setToken({
+      access_token: connection.accessToken,
+      refresh_token: connection.refreshToken,
+      token_type: 'Bearer',
+      expires_in: Math.floor((connection.expiresAt - Date.now()) / 1000)
+    });
+
+    const authResponse = await this.qbClient.refresh();
+    const tokenData = authResponse.getJson();
+
+    connection.accessToken = tokenData.access_token;
+    connection.refreshToken = tokenData.refresh_token;
+    connection.expiresAt = new Date(Date.now() + tokenData.expires_in * 1000);
+    await connection.save();
+
+    return connection;
+  }
+
+  // Xero methods
+  async getXeroAuthUrl(userId) {
+    const consentUrl = await this.xeroClient.buildConsentUrl();
+    return `${consentUrl}&state=user_${userId}`;
+  }
+
+  async handleXeroCallback(code, state) {
+    const userId = state.replace('user_', '');
+    const tokenSet = await this.xeroClient.apiCallback(code);
+
+    const connections = await this.xeroClient.updateTenants();
+    const tenantId = connections[0].tenantId;
+
+    const connection = new AccountingConnection({
+      user: userId,
+      platform: 'xero',
+      accessToken: tokenSet.access_token,
+      refreshToken: tokenSet.refresh_token,
+      tenantId: tenantId,
+      expiresAt: new Date(Date.now() + tokenSet.expires_in * 1000)
+    });
+
+    await connection.save();
+    return connection;
+  }
+
+  async refreshXeroToken(connection) {
+    await this.xeroClient.setTokenSet({
+      access_token: connection.accessToken,
+      refresh_token: connection.refreshToken,
+      expires_at: connection.expiresAt.getTime() / 1000
+    });
+
+    const tokenSet = await this.xeroClient.refreshToken();
+    connection.accessToken = tokenSet.access_token;
+    connection.refreshToken = tokenSet.refresh_token;
+    connection.expiresAt = new Date(tokenSet.expires_at * 1000);
+    await connection.save();
+
+    return connection;
+  }
+
+  // Sync expenses to accounting platform
+  async syncExpensesToAccounting(userId, platform) {
+    const connection = await AccountingConnection.findOne({ user: userId, platform });
+    if (!connection) throw new Error('No accounting connection found');
+
+    // Refresh token if needed
+    if (connection.expiresAt < new Date()) {
+      if (platform === 'quickbooks') {
+        await this.refreshQuickBooksToken(connection);
+      } else {
+        await this.refreshXeroToken(connection);
+      }
+    }
+
+    const expenses = await Expense.find({ user: userId, syncedToAccounting: { $ne: true } });
+
+    for (const expense of expenses) {
+      if (platform === 'quickbooks') {
+        await this.syncToQuickBooks(expense, connection);
+      } else {
+        await this.syncToXero(expense, connection);
+      }
+      expense.syncedToAccounting = true;
+      await expense.save();
+    }
+
+    return { synced: expenses.length };
+  }
+
+  async syncToQuickBooks(expense, connection) {
+    // Implement QuickBooks API call to create expense
+    const qbUrl = `https://quickbooks.api.intuit.com/v3/company/${connection.realmId}/purchase`;
+
+    const expenseData = {
+      "AccountRef": {
+        "value": "1", // Default expense account
+        "name": "Expense"
+      },
+      "PaymentType": "Cash",
+      "TxnDate": expense.date.toISOString().split('T')[0],
+      "Line": [{
+        "Amount": expense.amount,
+        "DetailType": "AccountBasedExpenseLineDetail",
+        "AccountBasedExpenseLineDetail": {
+          "AccountRef": {
+            "value": "1"
+          }
+        }
+      }]
+    };
+
+    await axios.post(qbUrl, expenseData, {
+      headers: {
+        'Authorization': `Bearer ${connection.accessToken}`,
+        'Content-Type': 'application/json'
+      }
+    });
+  }
+
+  async syncToXero(expense, connection) {
+    // Implement Xero API call
+    await this.xeroClient.setTokenSet({
+      access_token: connection.accessToken,
+      refresh_token: connection.refreshToken
+    });
+
+    const expenseData = {
+      Type: 'ACCPAY',
+      Contact: {
+        Name: expense.merchant || 'Expense'
+      },
+      Date: expense.date.toISOString().split('T')[0],
+      DueDate: expense.date.toISOString().split('T')[0],
+      LineItems: [{
+        Description: expense.description,
+        Quantity: 1,
+        UnitAmount: expense.amount,
+        AccountCode: '400' // Expense account
+      }],
+      Status: 'AUTHORISED'
+    };
+
+    await this.xeroClient.accountingApi.createInvoices(connection.tenantId, { invoices: [expenseData] });
+  }
+
+  // Get connected platforms for user
+  async getUserConnections(userId) {
+    return await AccountingConnection.find({ user: userId });
+  }
+
+  // Disconnect platform
+  async disconnectPlatform(userId, platform) {
+    await AccountingConnection.findOneAndDelete({ user: userId, platform });
+  }
+}
+
+module.exports = new AccountingService();
\ No newline at end of file