An optical connector (100) defining a receiving space (101) includes an insulative housing (1), a plurality of contacts (2) and an optical fiber module (3) retained in the insulative housing (1). The insulative housing (1) has a base (12) and a tongue (13) extending forwardly from the base (12). The base (12) has a front wall (121) and a cavity (125) extending therethrough. The optical fiber module (3) is received in the cavity (125) and has at least a position post (32) extending forwardly beyond the front wall (121). A protecting mechanism (126) extends into the receiving space (101). The protecting mechanism (126) has a front end (1260) arranged at front of the position post (32) to make the receiving space (101) having a first insertion length (X) and a second insertion length (Y). The second insertion length (Y) is larger than the first insertion length (X).