A writing instrument has a main body having front and rear ends and a writing tip at the front end, and a cap detachably attachable to a front portion of the main body to cover the writing tip and detachably attachable to a rear portion of the main body. A first opening is provided in the rear portion of the main body, and a second opening is provided in the cap. The first and second openings are alignable with one another when the cap is detachably attached to the rear portion of the main body to enable a tether to be threaded through the aligned openings for tethering the writing instrument to an object. Alternatively, the tether may be threaded through only the first opening at the rear portion of the main body for tethering the main body to an object. The cap may have a third opening at or near an end thereof, and the tether may alternatively be threaded through the third opening for tethering the cap to an object. This multi-mode tethering greatly increases the versatility of the writing instrument, enabling it to be attached to objects in different ways.