diff --git a/erpnext/manufacturing/doctype/work_order/work_order.py b/erpnext/manufacturing/doctype/work_order/work_order.py
index 3f470ccd216..2454341dc39 100644
--- a/erpnext/manufacturing/doctype/work_order/work_order.py
+++ b/erpnext/manufacturing/doctype/work_order/work_order.py
@@ -295,6 +295,10 @@ class WorkOrder(Document):
 		self.validate_subcontracting_inward_order()
 
 	def validate_dates(self):
+		if self.planned_start_date and self.planned_end_date:
+			if get_datetime(self.planned_end_date) < get_datetime(self.planned_start_date):
+				frappe.throw(_("Planned End Date cannot be before Planned Start Date"))
+
 		if self.actual_start_date and self.actual_end_date:
 			if self.actual_end_date < self.actual_start_date:
 				frappe.throw(_("Actual End Date cannot be before Actual Start Date"))