Scattering rates for holes in wurtzite GaN are investigated theoretically taking into account six valence bands including the spin-orbit interaction. Scattering rates for acoustic deformation potential, piezoelectric acoustic phonon, polar optical phonon, and impurity scattering are formulated. Results are given for intra- and interband processes, and their role in understanding transport measurements is discussed. The scattering probabilities are anisotropic owing to incomplete initial and final state overlap, to nonuniform final state density, and angular dispersion of the phonon modes. In addition, the level of detail obtained is sufficient to examine the modifications of the scattering rates with the application of uniaxial stress, and numerical results are presented.