A grab handle assembly for a vehicle includes a sleeve for attaching to the vehicle, an insert receivable in the sleeve, and a grab handle positioned on an end of the insert. A locking member is provided to adjustably fix a position of the grab handle with respect to the sleeve. The locking member includes a locking pin and a cam lock mechanism to hold the insert with respect to the sleeve. A rotation prevention surface may be provided on the locking pin to prevent the locking pin from rotating with respect to the sleeve and the insert. A locking force provided by the locking member may be preset.