diff --git a/App/app/(portal)/payments/actions.ts b/App/app/(portal)/payments/actions.ts
index 4dc4219..2e9f547 100644
--- a/App/app/(portal)/payments/actions.ts
+++ b/App/app/(portal)/payments/actions.ts
@@ -140,16 +140,20 @@ export async function markPaid({
   poId,
   paymentRef,
   paymentAmount,
+  paymentDate,
 }: {
   poId: string;
   paymentRef: string;
   paymentAmount?: number; // if omitted, treat as full remaining amount
+  paymentDate: string; // ISO date (yyyy-mm-dd) entered by Accounts
 }): Promise<ActionResult> {
   const session = await auth();
   if (!session?.user) return { error: "Unauthorized" };
 
-  const parsed = processPaymentSchema.safeParse({ paymentRef, paymentAmount });
-  if (!parsed.success) return { error: "Payment reference is required." };
+  const parsed = processPaymentSchema.safeParse({ paymentRef, paymentAmount, paymentDate });
+  if (!parsed.success) return { error: parsed.error.errors[0]?.message ?? "Validation failed" };
+
+  const enteredPaymentDate = parsed.data.paymentDate;
 
   const po = await db.purchaseOrder.findUnique({
     where: { id: poId },
@@ -175,14 +179,15 @@ export async function markPaid({
       where: { id: poId },
       data: {
         status: "PAID_DELIVERED",
-        paidAt: new Date(),
+        paidAt: enteredPaymentDate,
+        paymentDate: enteredPaymentDate,
         paymentRef: parsed.data.paymentRef,
         paidAmount: newPaidAmount,
         actions: {
           create: {
             actionType: "PAYMENT_SENT",
             actorId: session.user.id,
-            metadata: { paymentRef: parsed.data.paymentRef },
+            metadata: { paymentRef: parsed.data.paymentRef, paymentDate: enteredPaymentDate.toISOString() },
           },
         },
       },
@@ -206,6 +211,7 @@ export async function markPaid({
       data: {
         status: "PARTIALLY_PAID",
         paymentRef: parsed.data.paymentRef,
+        paymentDate: enteredPaymentDate,
         paidAmount: newPaidAmount,
         actions: {
           create: {
@@ -215,6 +221,7 @@ export async function markPaid({
               paymentRef: parsed.data.paymentRef,
               paymentAmount: paying,
               totalPaid: newPaidAmount,
+              paymentDate: enteredPaymentDate.toISOString(),
             },
           },
         },
diff --git a/App/app/(portal)/payments/history/page.tsx b/App/app/(portal)/payments/history/page.tsx
index 28e564b..870f703 100644
--- a/App/app/(portal)/payments/history/page.tsx
+++ b/App/app/(portal)/payments/history/page.tsx
@@ -130,7 +130,7 @@ export default async function PaymentHistoryPage({ searchParams }: Props) {
                   {formatCurrency(Number(po.totalAmount), po.currency)}
                 </td>
                 <td className="px-4 py-3 text-neutral-500">
-                  {po.paidAt ? formatDate(po.paidAt) : "—"}
+                  {po.paymentDate ? formatDate(po.paymentDate) : po.paidAt ? formatDate(po.paidAt) : "—"}
                 </td>
               </tr>
             ))}
diff --git a/App/app/(portal)/payments/payment-actions.tsx b/App/app/(portal)/payments/payment-actions.tsx
index 03125e7..489be81 100644
--- a/App/app/(portal)/payments/payment-actions.tsx
+++ b/App/app/(portal)/payments/payment-actions.tsx
@@ -12,14 +12,23 @@ interface Props {
   paidAmount?: number;
 }
 
+// Today's date as a local yyyy-mm-dd string (for <input type="date"> default + max)
+function todayLocal(): string {
+  const d = new Date();
+  const off = d.getTimezoneOffset();
+  return new Date(d.getTime() - off * 60_000).toISOString().slice(0, 10);
+}
+
 export function PaymentActions({ poId, poStatus, totalAmount = 0, paidAmount = 0 }: Props) {
   const router = useRouter();
   const [ref, setRef] = useState("");
   const [amount, setAmount] = useState<string>("");
+  const [paymentDate, setPaymentDate] = useState<string>(todayLocal());
   const [pending, setPending] = useState(false);
   const [error, setError] = useState("");
 
   const remaining = totalAmount - paidAmount;
+  const today = todayLocal();
 
   async function handleProcessPayment() {
     setPending(true);
@@ -32,6 +41,8 @@ export function PaymentActions({ poId, poStatus, totalAmount = 0, paidAmount = 0
   async function handleMarkPaid(e: React.FormEvent, forceFullPayment = false) {
     e.preventDefault();
     if (!ref.trim()) { setError("Payment reference is required."); return; }
+    if (!paymentDate) { setError("Payment date is required."); return; }
+    if (paymentDate > today) { setError("Payment date cannot be in the future."); return; }
 
     const paymentAmount = forceFullPayment ? remaining : (parseFloat(amount) || undefined);
 
@@ -46,7 +57,7 @@ export function PaymentActions({ poId, poStatus, totalAmount = 0, paidAmount = 0
 
     setPending(true);
     setError("");
-    const result = await markPaid({ poId, paymentRef: ref, paymentAmount });
+    const result = await markPaid({ poId, paymentRef: ref, paymentAmount, paymentDate });
     if ("error" in result) { setError(result.error); setPending(false); }
     else { setPending(false); router.refresh(); }
   }
@@ -88,6 +99,16 @@ export function PaymentActions({ poId, poStatus, totalAmount = 0, paidAmount = 0
             onChange={(e) => setRef(e.target.value)}
             className="flex-1 rounded-lg border border-neutral-300 px-3 py-2 text-sm focus:border-primary-500 focus:outline-none focus:ring-2 focus:ring-primary-500/20"
           />
+          <input
+            type="date"
+            aria-label="Payment date"
+            title="Payment date"
+            value={paymentDate}
+            max={today}
+            required
+            onChange={(e) => setPaymentDate(e.target.value)}
+            className="w-full sm:w-40 rounded-lg border border-neutral-300 px-3 py-2 text-sm focus:border-primary-500 focus:outline-none focus:ring-2 focus:ring-primary-500/20"
+          />
           <input
             type="number"
             placeholder={`Amount (max ${remaining.toFixed(2)})`}
diff --git a/App/components/po/po-detail.tsx b/App/components/po/po-detail.tsx
index 6dca391..0f08562 100644
--- a/App/components/po/po-detail.tsx
+++ b/App/components/po/po-detail.tsx
@@ -20,6 +20,7 @@ type PoWithRelations = {
   dateRequired: Date | null;
   managerNote: string | null;
   paymentRef: string | null;
+  paymentDate?: Date | null;
   paidAmount?: import("@prisma/client").Prisma.Decimal | null;
   piQuotationNo?: string | null;
   piQuotationDate?: Date | null;
@@ -299,6 +300,7 @@ export async function PoDetail({ po, currentUserId, currentRole, readOnly = fals
           {po.requisitionNo && <div><dt className="text-neutral-500">Requisition No.</dt><dd className="font-medium text-neutral-900">{po.requisitionNo}</dd></div>}
           {po.requisitionDate && <div><dt className="text-neutral-500">Requisition Date</dt><dd className="font-medium text-neutral-900">{formatDate(po.requisitionDate)}</dd></div>}
           {po.paymentRef && <div><dt className="text-neutral-500">Payment Ref</dt><dd className="font-mono text-sm text-neutral-900">{po.paymentRef}</dd></div>}
+          {(po.paymentDate || po.paidAt) && <div><dt className="text-neutral-500">Payment Date</dt><dd className="font-medium text-neutral-900">{formatDate((po.paymentDate ?? po.paidAt)!)}</dd></div>}
         </dl>
         {po.placeOfDelivery && (
           <div className="mt-3 pt-3 border-t border-neutral-100 text-sm">
diff --git a/App/lib/validations/po.ts b/App/lib/validations/po.ts
index acc3936..3623cb0 100644
--- a/App/lib/validations/po.ts
+++ b/App/lib/validations/po.ts
@@ -65,6 +65,14 @@ export const requestEditsSchema = z.object({
 export const processPaymentSchema = z.object({
   paymentRef: z.string().min(1, "Payment reference is required"),
   paymentAmount: z.number().positive("Payment amount must be greater than 0").optional(),
+  paymentDate: z.coerce
+    .date({ required_error: "Payment date is required", invalid_type_error: "Payment date is required" })
+    .refine((d) => {
+      // Not in the future — compare against end of today (local)
+      const endOfToday = new Date();
+      endOfToday.setHours(23, 59, 59, 999);
+      return d.getTime() <= endOfToday.getTime();
+    }, "Payment date cannot be in the future"),
 });
 
 export const confirmReceiptSchema = z.object({
diff --git a/App/prisma/migrations/20260531000002_po_payment_date/migration.sql b/App/prisma/migrations/20260531000002_po_payment_date/migration.sql
new file mode 100644
index 0000000..892014d
--- /dev/null
+++ b/App/prisma/migrations/20260531000002_po_payment_date/migration.sql
@@ -0,0 +1,22 @@
+-- Add user-entered payment date to PurchaseOrder
+ALTER TABLE "PurchaseOrder" ADD COLUMN "paymentDate" TIMESTAMP(3);
+
+-- Backfill 1: fully-paid POs already carry paidAt — use it as the payment date
+UPDATE "PurchaseOrder"
+SET "paymentDate" = "paidAt"
+WHERE "paidAt" IS NOT NULL AND "paymentDate" IS NULL;
+
+-- Backfill 2: POs that have a payment reference but no payment date yet
+-- (e.g. partially-paid) — use the date the payment reference was first recorded,
+-- i.e. the earliest PAYMENT_SENT / PARTIAL_PAYMENT_CONFIRMED action.
+UPDATE "PurchaseOrder" po
+SET "paymentDate" = sub."firstPaymentActionAt"
+FROM (
+  SELECT "poId", MIN("createdAt") AS "firstPaymentActionAt"
+  FROM "POAction"
+  WHERE "actionType" IN ('PAYMENT_SENT', 'PARTIAL_PAYMENT_CONFIRMED')
+  GROUP BY "poId"
+) sub
+WHERE po."id" = sub."poId"
+  AND po."paymentDate" IS NULL
+  AND po."paymentRef" IS NOT NULL;
diff --git a/App/prisma/schema.prisma b/App/prisma/schema.prisma
index 9a9b9e1..bc23465 100644
--- a/App/prisma/schema.prisma
+++ b/App/prisma/schema.prisma
@@ -250,6 +250,7 @@ model PurchaseOrder {
   projectCode         String?
   managerNote         String?
   paymentRef          String?
+  paymentDate         DateTime?
   paidAmount          Decimal?  @db.Decimal(12, 2)
   piQuotationNo       String?
   piQuotationDate     DateTime?
diff --git a/App/tests/integration/payment-actions.test.ts b/App/tests/integration/payment-actions.test.ts
index b94ead1..a6ace55 100644
--- a/App/tests/integration/payment-actions.test.ts
+++ b/App/tests/integration/payment-actions.test.ts
@@ -19,6 +19,7 @@ import {
 } from "./helpers";
 
 const PREFIX = "INTTEST_PAYMENT_";
+const TODAY = new Date().toISOString().slice(0, 10); // yyyy-mm-dd, used for payment date
 let techId: string;
 let managerId: string;
 let accountsId: string;
@@ -91,13 +92,14 @@ describe("A-02 — mark PO as paid with reference number", () => {
 
     vi.mocked(auth).mockResolvedValue(makeSession(accountsId, "ACCOUNTS"));
     await processPayment({ poId });
-    const result = await markPaid({ poId, paymentRef: "NEFT/2026/001234" });
+    const result = await markPaid({ poId, paymentRef: "NEFT/2026/001234", paymentDate: TODAY });
     expect(result).toEqual({ ok: true });
 
     const po = await db.purchaseOrder.findUnique({ where: { id: poId } });
     expect(po?.status).toBe("PAID_DELIVERED");
     expect(po?.paymentRef).toBe("NEFT/2026/001234");
     expect(po?.paidAt).not.toBeNull();
+    expect(po?.paymentDate).not.toBeNull();
   });
 
   it("creates a PAYMENT_SENT action in the audit trail", async () => {
@@ -105,7 +107,7 @@ describe("A-02 — mark PO as paid with reference number", () => {
 
     vi.mocked(auth).mockResolvedValue(makeSession(accountsId, "ACCOUNTS"));
     await processPayment({ poId });
-    await markPaid({ poId, paymentRef: "TXN-9999" });
+    await markPaid({ poId, paymentRef: "TXN-9999", paymentDate: TODAY });
 
     const action = await db.pOAction.findFirst({ where: { poId, actionType: "PAYMENT_SENT" } });
     expect(action).not.toBeNull();
@@ -117,7 +119,17 @@ describe("A-02 — mark PO as paid with reference number", () => {
 
     vi.mocked(auth).mockResolvedValue(makeSession(accountsId, "ACCOUNTS"));
     await processPayment({ poId });
-    const result = await markPaid({ poId, paymentRef: "" });
+    const result = await markPaid({ poId, paymentRef: "", paymentDate: TODAY });
+    expect(result).toHaveProperty("error");
+  });
+
+  it("returns error when payment date is in the future", async () => {
+    const poId = await createApprovedPo(`${PREFIX}PaidFutureDate`);
+
+    vi.mocked(auth).mockResolvedValue(makeSession(accountsId, "ACCOUNTS"));
+    await processPayment({ poId });
+    const future = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString().slice(0, 10);
+    const result = await markPaid({ poId, paymentRef: "FUTURE-REF", paymentDate: future });
     expect(result).toHaveProperty("error");
   });
 
@@ -128,7 +140,7 @@ describe("A-02 — mark PO as paid with reference number", () => {
     vi.mocked(auth).mockResolvedValue(makeSession(accountsId, "ACCOUNTS"));
     vi.mocked(notify).mockClear();
     await processPayment({ poId });
-    await markPaid({ poId, paymentRef: "REF-42" });
+    await markPaid({ poId, paymentRef: "REF-42", paymentDate: TODAY });
 
     const calls = vi.mocked(notify).mock.calls.map((c) => c[0].event);
     expect(calls).toContain("PAYMENT_SENT");
@@ -141,7 +153,7 @@ describe("A-02 — mark PO as paid with reference number", () => {
     await processPayment({ poId });
 
     vi.mocked(auth).mockResolvedValue(makeSession(managerId, "MANAGER"));
-    const result = await markPaid({ poId, paymentRef: "MGR-REF" });
+    const result = await markPaid({ poId, paymentRef: "MGR-REF", paymentDate: TODAY });
     expect(result).toHaveProperty("error");
   });
 });