This work presents a theoretical study on the influence of the electron effective mass on the electron drift velocity in n-doped wurtzite GaN at moderate to high electric fields. This was used for a nonlinear quantum transport theory, based on a nonequilibrium ensemble formalism (MaxEnt-NESOM), which provides a set of coupled nonlinear integro-differential equations of evolution. It was found that the adopted value of the electron effective mass can produce a difference of up to 55% in the value of the electron drift velocity.