diff --git a/addons/web/static/src/js/view_form.js b/addons/web/static/src/js/view_form.js
index 52065001693..83faa5e8626 100644
--- a/addons/web/static/src/js/view_form.js
+++ b/addons/web/static/src/js/view_form.js
@@ -855,6 +855,16 @@ instance.web.FormView = instance.web.View.extend(instance.web.form.FieldManagerM
                     }
                 }
             }
+            // Heuristic to assign a proper sequence number for new records that
+            // are added in a dataset containing other lines with existing sequence numbers
+            if (!self.datarecord.id && self.fields.sequence &&
+                !_.has(values, 'sequence') && !_.isEmpty(self.dataset.cache)) {
+                // Find current max or min sequence (editable top/bottom)
+                var current = _[prepend_on_create ? "min" : "max"](
+                    _.map(self.dataset.cache, function(o){return o.values.sequence})
+                );
+                values['sequence'] = prepend_on_create ? current - 1 : current + 1;
+            }
             if (form_invalid) {
                 self.set({'display_invalid_fields': true});
                 first_invalid_field.focus();