An electrical connector assembly includes a connector housing, a terminal support and a terminal holder. The terminal support is integrally connected to the connector housing. The terminal support has therein a plurality of abreast arranged passages to receive a plurality of terminals. The terminal holder has a through bore which is so sized as to receive therein the terminal support. The terminal holder is formed at rear portions thereof a pair of openable portions. The terminal holder is to be incompletely and completely latched to one of the connector housing and the terminal support with the openable portion assuming the open and closed conditions, respectively.