diff --git a/components/payments/paymentController.js b/components/payments/paymentController.js
index 1d78a20..bc43ad1 100644
--- a/components/payments/paymentController.js
+++ b/components/payments/paymentController.js
@@ -58,3 +58,9 @@ exports.updateTransaction = catchAsync(async (req, res, next) => {
   const payment = await paymentService.updateTransaction(req.params.transactionId, req.body, actorId);
   return successResponse(res, 200, 'Transaction updated successfully', payment);
 });
+
+exports.cancelTransaction = catchAsync(async (req, res, next) => {
+  const actorId = req.user?._id;
+  const payment = await paymentService.cancelTransaction(req.params.transactionId, actorId);
+  return successResponse(res, 200, 'Transaction cancelled successfully', payment);
+});
diff --git a/components/payments/paymentRoutes.js b/components/payments/paymentRoutes.js
index 1093230..8f3895e 100644
--- a/components/payments/paymentRoutes.js
+++ b/components/payments/paymentRoutes.js
@@ -27,6 +27,7 @@ router.get('/admin/search', perm.requires(PERMISSIONS.PAYMENTS_SEARCH), paymentC
 router.get('/admin/get-one/:id', perm.requires(PERMISSIONS.PAYMENTS_READ), paymentController.getOne);
 router.put('/admin/update/:id', perm.requires(PERMISSIONS.PAYMENTS_UPDATE), validateUpdatePayment, paymentController.update);
 router.put('/admin/transactions/:transactionId', perm.requires(PERMISSIONS.PAYMENTS_UPDATE), validateUpdateTransaction, paymentController.updateTransaction);
+router.post('/admin/transactions/:transactionId/cancel', perm.requires(PERMISSIONS.PAYMENTS_UPDATE), paymentController.cancelTransaction);
 router.post('/admin/transactions/:paymentId', perm.requires(PERMISSIONS.PAYMENTS_UPDATE), validateAddTransaction, paymentController.createTransaction);
 router.delete('/admin/delete/:id', perm.requires(PERMISSIONS.PAYMENTS_DELETE), paymentController.delete);
 
diff --git a/components/payments/paymentService.js b/components/payments/paymentService.js
index b17c1d0..77f7498 100644
--- a/components/payments/paymentService.js
+++ b/components/payments/paymentService.js
@@ -20,6 +20,8 @@ const {
   normalizeDiscount,
   sanitizeNotes,
   isPaidTransaction,
+  isCancelledTransaction,
+  isActiveTransaction,
   sumPaidTransactions
 } = require('../../utils/paymentAmount');
 const logger = require('../../utils/logger');
@@ -56,7 +58,7 @@ const refreshPaymentTotals = async (payment) => {
   const transactions = await Transaction.find({ payment: payment._id }).lean();
   payment.paidAmount = sumPaidTransactions(transactions);
   const pending = transactions
-    .filter((trx) => !isPaidTransaction(trx))
+    .filter((trx) => isActiveTransaction(trx) && !isPaidTransaction(trx))
     .sort((a, b) => new Date(a.dueDate || 0) - new Date(b.dueDate || 0));
   payment.dueDate = pending[0]?.dueDate || payment.dueDate;
   await payment.save();
@@ -333,6 +335,9 @@ const addTransaction = async (paymentId, trxData, actorId = null) => {
 const updateTransaction = async (transactionId, body, actorId = null) => {
   const trx = await Transaction.findById(transactionId);
   if (!trx) throw new AppError('TRANSACTION_NOT_FOUND');
+  if (trx.status === 'cancelled') {
+    throw new AppError('VALIDATION_FAILED', {}, 'تراکنش لغوشده قابل ویرایش نیست.');
+  }
 
   const payment = await Payment.findById(trx.payment);
   if (!payment) throw new AppError('PAYMENT_NOT_FOUND');
@@ -373,6 +378,27 @@ const updateTransaction = async (transactionId, body, actorId = null) => {
   return getPaymentById(payment._id);
 };
 
+const cancelTransaction = async (transactionId, actorId = null) => {
+  const trx = await Transaction.findById(transactionId);
+  if (!trx) throw new AppError('TRANSACTION_NOT_FOUND');
+  if (trx.status === 'cancelled') {
+    throw new AppError('VALIDATION_FAILED', {}, 'این تراکنش قبلاً لغو شده است.');
+  }
+
+  const payment = await Payment.findById(trx.payment);
+  if (!payment) throw new AppError('PAYMENT_NOT_FOUND');
+
+  const previousStatus = payment.status;
+  trx.status = 'cancelled';
+  if (actorId) trx.recordedBy = actorId;
+  await trx.save();
+
+  await refreshPaymentTotals(payment);
+  emitPaymentStatusChangedIfNeeded(payment, previousStatus, actorId);
+
+  return getPaymentById(payment._id);
+};
+
 const getMyPayments = async (userId, query = {}) => {
   return getAllPayments({ ...query, userId });
 };
@@ -386,6 +412,7 @@ module.exports = {
   searchPayments,
   addTransaction,
   updateTransaction,
+  cancelTransaction,
   getMyPayments,
   createTransactionsForPayment,
   refreshPaymentTotals,
diff --git a/components/payments/transactionModel.js b/components/payments/transactionModel.js
index 1dd1ad1..09565b9 100644
--- a/components/payments/transactionModel.js
+++ b/components/payments/transactionModel.js
@@ -35,7 +35,7 @@ const transactionSchema = new mongoose.Schema({
   },
   status: {
     type: String,
-    enum: ['pending', 'paid'],
+    enum: ['pending', 'paid', 'cancelled'],
     default: 'pending',
     index: true
   }
diff --git a/utils/paymentAmount.js b/utils/paymentAmount.js
index 6b8ec5b..852d18f 100644
--- a/utils/paymentAmount.js
+++ b/utils/paymentAmount.js
@@ -24,13 +24,18 @@ const sanitizeNotes = (notes) => {
 
 const rialsToToman = (value) => Math.floor(toNonNegativeNumber(value) / 10);
 
+const isCancelledTransaction = (trx = {}) => String(trx.status || '').toLowerCase() === 'cancelled';
+
 const isPaidTransaction = (trx = {}) => {
+  if (isCancelledTransaction(trx)) return false;
   const status = String(trx.status || '').toLowerCase();
   if (status === 'pending') return false;
   if (status === 'paid') return true;
   return Boolean(trx.date);
 };
 
+const isActiveTransaction = (trx = {}) => !isCancelledTransaction(trx);
+
 const sumPaidTransactions = (transactions = []) => {
   if (!Array.isArray(transactions)) return 0;
   return transactions.reduce((sum, trx) => {
@@ -50,6 +55,8 @@ module.exports = {
   sanitizeNotes,
   rialsToToman,
   isPaidTransaction,
+  isCancelledTransaction,
+  isActiveTransaction,
   sumPaidTransactions,
   remainingPayable
 };
diff --git a/utils/paymentAmount.test.js b/utils/paymentAmount.test.js
index ca5ed9f..171b9e0 100644
--- a/utils/paymentAmount.test.js
+++ b/utils/paymentAmount.test.js
@@ -73,6 +73,16 @@ describe('paid vs pending transactions', () => {
     assert.equal(isPaidTransaction({ status: 'pending', amount: 2_000_000 }), false);
     assert.equal(isPaidTransaction({ status: 'paid', amount: 8_000_000 }), true);
   });
+
+  it('ignores cancelled transactions in paid totals', () => {
+    const transactions = [
+      { amount: 5_000_000, status: 'paid', date: '2026-08-03' },
+      { amount: 5_000_000, status: 'cancelled' },
+      { amount: 2_000_000, status: 'pending', dueDate: '2026-08-23' }
+    ];
+    assert.equal(sumPaidTransactions(transactions), 5_000_000);
+    assert.equal(isPaidTransaction({ status: 'cancelled', amount: 5_000_000, date: '2026-08-03' }), false);
+  });
 });
 
 describe('sanitizeNotes', () => {