  This talk discusses theoretical aspects of tests of CPT and Lorentz Symmetry
that will in principle be possible with trapped antihydrogen. The framework is
the standard-model extension, which admits minuscule violations of CPT and
Lorentz symmetry in a general manner without giving up other features of the
standard model of particle physics. Spectroscopic transitions in hydrogen and
antihydrogen that exhibit leading-order effects are identified. Such
comparisons of spectral frequencies in antimatter with the corresponding
frequencies in regular matter will bound parameter combinations that are not
accessible with regular-matter atoms alone.
