The present invention relates generally to ferrule holders and associated fiber optic connectors used in optical communications networks, optical devices, and the like to optically couple optical fibers. More specifically, the present invention relates to a ferrule holder and an associated fiber optic connector having improved anti-withdrawal and anti-rotation features, such as a twin-threaded configuration, a single-threaded configuration, a splined configuration, a broached configuration, a counter-bored configuration, a dented configuration, a finned configuration, etc. These anti-withdrawal and anti-rotation features assist in holding an optical fiber in secure optical and/or physical contact with a ferrule within the ferrule holder and associated fiber optic connector.