Abstract: Structures and methods for frequency shifting rotational harmonics in MEMS devices are disclosed. An illustrative MEMS device can include a substrate, a sense electrode coupled to the substrate, and a proof mass adjacent to the sense electrode. A number of non-uniformly dispersed holes or openings on the proof mass can be configured to alter the distribution of mass within the proof mass. During operation, the presence of the holes or openings alters the frequency at which the proof mass rotates about a centerline in a rotational mode, reducing the introduction of harmonics into the drive and sense systems.