diff --git a/src/pretix/static/pretixbase/js/addressform.js b/src/pretix/static/pretixbase/js/addressform.js
index 5933fb98c6..c4298b97f3 100644
--- a/src/pretix/static/pretixbase/js/addressform.js
+++ b/src/pretix/static/pretixbase/js/addressform.js
@@ -166,6 +166,23 @@ $(function () {
         };
         update();
         dependencies.on("change", update);
+
+        if (dependents.vat_id && dependents.transmission_type && dependents.transmission_peppol_participant_id) {
+            // In Belgium, the VAT ID is built from "BE" + the company ID. The Peppol ID also needs to be built
+            // from the company ID with ID scheme 0208. We can save users some knowing and typing by filling this in!
+            if (!dependents.transmission_peppol_participant_id.val()) {
+                const fill_peppol_id = function () {
+                    const vatId = dependents.vat_id.val();
+                    if (vatId && vatId.startsWith("BE") && dependents.transmission_type.val() === "peppol" && autofill_peppol_id) {
+                        dependents.transmission_peppol_participant_id.val("0201:" + vatId.substring(2))
+                    }
+                }
+                dependents.vat_id.add(dependents.transmission_type).on("change", fill_peppol_id);
+                dependents.transmission_peppol_participant_id.one("change", () => {
+                    dependents.vat_id.add(dependents.transmission_type).unbind("change", fill_peppol_id)
+                });
+            }
+        }
     });
 
 });