A fiber optic connector includes a plug-in unit, a connecting unit, and a sleeving unit. The plug-in unit includes a switch member that is operable to move between a locking position and an adjusting position. The connecting unit includes a surrounding body that is formed with two through grooves. When the switch member is at the adjusting position, the switch member is moved away from of the through grooves and the connecting unit is operable to be separated from the plug-in unit. When the switch member is at the locking position, the switch member is moved into one of the through grooves to prevent separation of the connecting unit from the plug-in unit.