A multiple fiber push-on (MPO) optical connector is provided having a ferrule configured to house multiple optical fibers and including a stepped portion extending from at least one pair of opposing exterior surfaces of the ferrule. A one-piece housing-backpost is provided having a distal end in a connection direction and a proximal end in a cable direction. The one-piece housing-backpost is configured to receive a ferrule spring and the ferrule from the distal end. The housing-backpost includes at least one resiliently-deformable ferrule-retaining protrusion extending from a sidewall to engage the corresponding stepped portion of the ferrule. The resiliently-deformable ferrule-retaining protrusion is configured to deform towards the housing-backpost interior sidewall as the ferrule is inserted from the distal end and to extend outward against the stepped portion of the ferrule when the ferrule is seated in the housing-backpost to maintain the ferrule in the housing-backpost.