This paper presents recent work on ferroelectric-piezoelectric lead zirconate titanate (PZT) RF MEMS resonators. Several research topics are introduced including design modifications that improve out-of-band rejection by 35dB, a demonstration of a high rejection (∼117dB) parallel resonant mode with DC bias tunable rejection, a MEMS support design for the mitigation of anchor loss, and a numerical electrode shaping design technique that permits the excitation of arbitrary modes in arbitrary geometries.