Abstract: A strain-relief end bell for an electrical connector assembly includes a ratcheting mechanism that allows the end bell to resist vibration-induced decoupling once it is threaded onto an electrical connector. The ratcheting mechanism includes a retainer ring that is seated between an internally-threaded coupling ring and an annular fitting around which the coupling ring is rotatably mounted. The retainer ring is fixed to the coupling ring so that both rings are rotatable together. The inner peripheral edge of the retainer ring has a plurality of equidistantly-spaced detents that engage a plurality of rotational bearings on the annular fitting as the coupling ring and the retainer ring are rotated with respect to the annular fitting. The engagement between the detents and the bearings creates a ratcheting effect that restrains the coupling ring from rotating with respect to the fitting unless a manual effort is applied to it.