A steel rod in the neck of an ukulele meant to prevent the neck from twisting due to the tension of the strings or climatic influence. The rod can be adjusted with a hex wrench to change the bending of the neck. Thus, the action can also be changed. If the rod is too tense, buzz can appear; if it is too loose, string action may be too high.

Most ukuleles do not have a truss rod because it is assumed that the tension of gut or nylon strings needs no compensation. Examples for ukuleles with a truss rod are Pono MHTSH and Pono MB.