Abstract: A universal armband assembly retains a cuboidal, electronic device in adjacency to a user's arm, and includes an armband and a resilient device-retainer formation. The armband includes a band-to-retainer interface portion and a strap portion. The band-to-retainer interface portion includes a strap-letting aperture and an outer interface portion end. The strap portion extends from the band-to-retainer interface portion in a direction opposite the outer interface portion end. The device-retainer formation is formed from a resilient unibody material construction, is attached to the band-to-retainer interface portion, and is configured to define a relaxed interior volume when in a relaxed state. The device-retainer formation is actuable to define an actuated interior volume, which interior volume receives the electronic device. Restorative forces of the resilient unibody material retain the electronic device within the actuated interior volume.