diff --git a/addons/purchase/views/purchase_views.xml b/addons/purchase/views/purchase_views.xml
index e95572ab67e..6046aed830d 100644
--- a/addons/purchase/views/purchase_views.xml
+++ b/addons/purchase/views/purchase_views.xml
@@ -167,7 +167,7 @@
                     <button name="button_draft" states="cancel" string="Set to Draft" type="object" />
                     <button name="button_cancel" states="draft,to approve,sent,purchase" string="Cancel" type="object" />
                     <button name="button_done" type="object" string="Lock" states="purchase"/>
-                    <button name="button_unlock" type="object" string="Unlock" states="done"/>
+                    <button name="button_unlock" type="object" string="Unlock" states="done" groups="purchase.group_purchase_manager"/>
                     <field name="state" widget="statusbar" statusbar_visible="draft,sent,purchase" readonly="1"/>
                 </header>
                 <sheet>