diff --git a/erpnext/stock/doctype/delivery_note/delivery_note.py b/erpnext/stock/doctype/delivery_note/delivery_note.py
index 3a056500b542..ba6e247d2e41 100644
--- a/erpnext/stock/doctype/delivery_note/delivery_note.py
+++ b/erpnext/stock/doctype/delivery_note/delivery_note.py
@@ -138,6 +138,7 @@ def validate(self):
 		self.validate_uom_is_integer("stock_uom", "stock_qty")
 		self.validate_uom_is_integer("uom", "qty")
 		self.validate_with_previous_doc()
+		self.validate_duplicate_serial_nos()
 
 		from erpnext.stock.doctype.packed_item.packed_item import make_packing_list
 
@@ -412,6 +413,21 @@ def get_product_bundle_list(self):
 			pluck="name",
 		)
 
+	def validate_duplicate_serial_nos(self):
+		serial_nos = []
+		for item in self.items:
+			if not item.serial_no:
+				continue
+
+			for serial_no in item.serial_no.split("\n"):
+				if serial_no in serial_nos:
+					frappe.throw(
+						_("Row #{0}: Serial No {1} is already selected.").format(item.idx, serial_no),
+						title=_("Duplicate Serial No"),
+					)
+				else:
+					serial_nos.append(serial_no)
+
 
 def update_billed_amount_based_on_so(so_detail, update_modified=True):
 	from frappe.query_builder.functions import Sum
diff --git a/erpnext/stock/doctype/delivery_note/test_delivery_note.py b/erpnext/stock/doctype/delivery_note/test_delivery_note.py
index 2565d1b76d19..2acfd84d9440 100644
--- a/erpnext/stock/doctype/delivery_note/test_delivery_note.py
+++ b/erpnext/stock/doctype/delivery_note/test_delivery_note.py
@@ -1211,6 +1211,38 @@ def test_batch_expiry_for_delivery_note(self):
 
 		self.assertTrue(return_dn.docstatus == 1)
 
+	def test_duplicate_serial_no_in_delivery_note(self):
+		# Step - 1: Create Serial Item
+		serial_item = make_item(
+			properties={
+				"is_stock_item": 1,
+				"has_serial_no": 1,
+				"serial_no_series": frappe.generate_hash("", 10) + ".###",
+			}
+		).name
+
+		# Step - 2: Inward Stock
+		se = make_stock_entry(item_code=serial_item, target="_Test Warehouse - _TC", qty=4)
+
+		# Step - 3: Create Delivery Note with Duplicare Serial Nos
+		serial_nos = se.items[0].serial_no.split("\n")
+		dn = create_delivery_note(
+			item_code=serial_item,
+			warehouse="_Test Warehouse - _TC",
+			qty=2,
+			do_not_save=True,
+		)
+		dn.items[0].serial_no = "\n".join(serial_nos[:2])
+		dn.append("items", dn.items[0].as_dict())
+
+		# Test - 1: ValidationError should be raised
+		self.assertRaises(frappe.ValidationError, dn.save)
+
+		# Step - 4: Submit Delivery Note with unique Serial Nos
+		dn.items[1].serial_no = "\n".join(serial_nos[2:])
+		dn.save()
+		dn.submit()
+
 	def tearDown(self):
 		frappe.db.rollback()
 		frappe.db.set_single_value("Selling Settings", "dont_reserve_sales_order_qty_on_sales_return", 0)