diff --git a/addons/sale/data/mail_data.xml b/addons/sale/data/mail_data.xml
index 957777fc3bf..af9e49da8c2 100644
--- a/addons/sale/data/mail_data.xml
+++ b/addons/sale/data/mail_data.xml
@@ -80,7 +80,7 @@
         <record id="email_template_edi_sale" model="mail.template">
             <field name="name">Sales Order: Send by email</field>
             <field name="model_id" ref="sale.model_sale_order"/>
-            <field name="subject">${object.company_id.name} ${object.state in ('draft', 'sent') and 'Quotation' or 'Order'} (Ref ${object.name or 'n/a' })</field>
+            <field name="subject">${object.company_id.name} ${object.state in ('draft', 'sent') and (ctx.get('proforma') and 'Proforma' or 'Quotation') or 'Order'} (Ref ${object.name or 'n/a' })</field>
             <field name="email_from">${(object.user_id.email_formatted or user.email_formatted) | safe}</field>
             <field name="partner_to">${object.partner_id.id}</field>
             <field name="body_html" type="html">