A retainer for releasably securing a headset earphone assembly of the type having a pair of pin receiving recesses therein to a flexible helmet in which a relatively rigid frame is formed with an outwardly opening peripheral channel adapted releasably to receive a portion of the flexible helmet body surrounding an opening therein adjacent to the ear of a wearer. A pair of housings formed by the rigid frame receive plates for sliding movement inwardly and outwardly of the frame opening which is so shaped that an earphone assembly placed therein is oriented with its pin receiving recesses aligned with projections on the sliding plates to permit the projections to be moved into the recesses and to be releasably locked into position securely to hold the headset assembly onto the flexible helmet.