diff --git a/erpnext/buying/doctype/request_for_quotation/mapper.py b/erpnext/buying/doctype/request_for_quotation/mapper.py
index 643f4824fe7..e3bb05bc946 100644
--- a/erpnext/buying/doctype/request_for_quotation/mapper.py
+++ b/erpnext/buying/doctype/request_for_quotation/mapper.py
@@ -58,25 +58,26 @@ def make_supplier_quotation_from_rfq(
 @frappe.whitelist(methods=["POST"])
 def create_supplier_quotation(doc: str | Document | dict):
 	doc = frappe.parse_json(doc)
+	supplier = doc.get("supplier")
 
-	if frappe.session.user not in frappe.get_all(
-		"Portal User", {"parent": doc.get("supplier")}, pluck="user"
-	):
+	if frappe.session.user not in frappe.get_all("Portal User", {"parent": supplier}, pluck="user"):
 		frappe.throw(_("Not Permitted"), frappe.PermissionError)
 
+	validate_existing_supplier_quotation(supplier, doc.get("items"))
+
 	sq_doc = frappe.get_doc(
 		{
 			"doctype": "Supplier Quotation",
-			"supplier": doc.get("supplier"),
+			"supplier": supplier,
 			"terms": doc.get("terms"),
 			"company": doc.get("company"),
 			"currency": doc.get("currency")
-			or get_party_account_currency("Supplier", doc.get("supplier"), doc.get("company")),
+			or get_party_account_currency("Supplier", supplier, doc.get("company")),
 			"buying_price_list": doc.get("buying_price_list")
 			or frappe.db.get_single_value("Buying Settings", "buying_price_list"),
 		}
 	)
-	add_items(sq_doc, doc.get("supplier"), doc.get("items"))
+	add_items(sq_doc, supplier, doc.get("items"))
 	sq_doc.flags.ignore_permissions = True
 	sq_doc.run_method("set_missing_values")
 	sq_doc.save()
@@ -84,6 +85,45 @@ def create_supplier_quotation(doc: str | Document | dict):
 	return sq_doc.name
 
 
+def validate_existing_supplier_quotation(supplier, items):
+	request_for_quotations = {item.get("parent") for item in items if item.get("parent")}
+	if not request_for_quotations:
+		return
+
+	rfq = frappe.qb.DocType("Request for Quotation")
+	(
+		frappe.qb.from_(rfq)
+		.select(rfq.name)
+		.where(rfq.name.isin(request_for_quotations))
+		.orderby(rfq.name)
+		.for_update()
+	).run()
+
+	sq = frappe.qb.DocType("Supplier Quotation")
+	sqi = frappe.qb.DocType("Supplier Quotation Item")
+	existing_quotation = (
+		frappe.qb.from_(sq)
+		.inner_join(sqi)
+		.on(sq.name == sqi.parent)
+		.select(sq.name, sqi.request_for_quotation)
+		.where(
+			(sq.docstatus < 2)
+			& (sq.supplier == supplier)
+			& (sqi.request_for_quotation.isin(request_for_quotations))
+		)
+		.limit(1)
+	).run(as_dict=True)
+
+	if existing_quotation:
+		existing_quotation = existing_quotation[0]
+		frappe.throw(
+			_("Supplier Quotation {0} already exists against Request for Quotation {1}").format(
+				frappe.bold(existing_quotation.name),
+				frappe.bold(existing_quotation.request_for_quotation),
+			)
+		)
+
+
 def add_items(sq_doc, supplier, items):
 	for data in items:
 		if isinstance(data, dict):
diff --git a/erpnext/buying/doctype/request_for_quotation/test_request_for_quotation.py b/erpnext/buying/doctype/request_for_quotation/test_request_for_quotation.py
index ee4cae18782..14ecd284f96 100644
--- a/erpnext/buying/doctype/request_for_quotation/test_request_for_quotation.py
+++ b/erpnext/buying/doctype/request_for_quotation/test_request_for_quotation.py
@@ -200,6 +200,18 @@ class TestRequestforQuotation(ERPNextTestSuite):
 		self.assertEqual(supplier_quotation_doc.get("items")[0].qty, 5)
 		self.assertEqual(supplier_quotation_doc.get("items")[0].amount, 500)
 
+	def test_make_duplicate_supplier_quotation_from_portal(self):
+		rfq = make_request_for_quotation()
+		rfq.supplier = rfq.suppliers[0].supplier
+		supplier_quotation = frappe.get_doc("Supplier Quotation", create_supplier_quotation(rfq))
+		supplier_quotation.submit()
+
+		with self.assertRaisesRegex(frappe.ValidationError, "already exists"):
+			create_supplier_quotation(rfq)
+
+		supplier_quotation.cancel()
+		self.assertTrue(create_supplier_quotation(rfq))
+
 	def test_make_multi_uom_supplier_quotation(self):
 		item_code = "_Test Multi UOM RFQ Item"
 		if not frappe.db.exists("Item", item_code):
diff --git a/erpnext/templates/pages/rfq.html b/erpnext/templates/pages/rfq.html
index 8d55d6b47e1..d2a9382dc6b 100644
--- a/erpnext/templates/pages/rfq.html
+++ b/erpnext/templates/pages/rfq.html
@@ -13,7 +13,7 @@
 {% endblock %}
 
 {% block header_actions %}
-{% if doc.items %}
+{% if doc.items and not doc.rfq_links %}
 <button class="btn btn-primary btn-sm"
     type="button">
     {{ _("Make Quotation") }}</button>