  An overview of recent progress on testing Lorentz and CPT symmetry using
Penning traps is presented. The theory of quantum electrodynamics with
Lorentz-violating operators of mass dimensions up to six is summarized.
Dominant shifts in the cyclotron and anomaly frequencies of the confined
particles and antiparticles due to Lorentz and CPT violation are derived.
Existing results of the comparisons of charge-to-mass ratios and magnetic
moments involving protons, antiprotons, electrons, and positrons are used to
constrain various coefficients for Lorentz violation.
