Exhibit 22.1 SUBSIDIARIES Littelfuse, S.A. de C.V. Littelfuse do Brasil Ltda. Littelfuse do Amazonia, Ltda. Watseka LF, Inc. Littelfuse, B.V. Littelfuse, A.G. Littelfuse Limited Littelfuse Ireland Development Co., Ltd. Littelfuse Ireland Limited Littelfuse U.K. Ltd. Littelfuse Ireland Holding Ltd. REMPAT Holding B.V. REMPAT Financial B.V. Littelfuse Far East Pte Ltd. Littelfuse HK Limited Suzhou Littelfuse OVS Ltd. Littelfuse KK Littelfuse Triad Inc. Littelfuse Phils Inc. Littelfuse S&L, Inc. Teccor Electronics, Inc. Teccor Delaware, Inc. Teccor GP, Inc. Teccor Electronics L.P. Teccor Electronics Mexico Holdings LLC Teccor de Mexico s. de. R.L. de C.V.