Abstract: A fiber optic adapter includes: an outer casing that has a plurality of connecting holes, a plurality of installation slots disposed in front of and spatially communicated with the connecting holes, and a plurality of insertion slots disposed behind and spatially communicated with the connecting holes; a position-limiting member that is fixed to the outer casing, and that includes a main plate portion, two side plate portions, a plurality of resilient plate portions disposed obliquely on the main and side plate portions, and a plurality of protruding portions protruding from the main and side plate portions; and a plurality of mounting seats that are inserted removably into the installation slots.