Abstract: Marking instrument having a cap with a sound producing apparatus mounted therein. The sound producing apparatus includes a sound generating electronic member along with a switch and an optional button for controlling the mode of operation of the switch for determining whether the sound and/or music is generated thereby. The sound producing apparatus is retained within the cap between an intermediately positioned shoulder member and a retaining ring extending into the upper opening of the cap. The retaining ring defines an orifice through which the button member or switch means of the electronic member may extend. The retaining ring is preferably formed as a single integral member with a clip for facilitating mounting thereof with respect to the marking instrument cap to facilitate retaining of the clip member extending longitudinally along the cap of the writing instrument as well as holding the retaining ring within the opening of the cap for fixedly holding the sound producing apparatus therein.