Prescribed fire is an important management tool used in the restoration of Sierra Nevada mixed conifer forests where fire has been suppressed over the last century. It is not well known, however, how the timing of prescribed fire affects wildlife populations. We used model selection and multi-model inference methods to compare the effects of early (spring and early summer) and late (late summer and fall) season prescribed fires on small mammal populations, based on 4 years of mark-recapture data collected in Sequoia National Park, California. The effects of prescribed fires on four small mammal metrics were evaluated: deer mouse (Peromyscus maniculatus) densities, deer mouse age ratios, lodgepole chipmunk (Neotamias speciosus) densities, and total small mammal biomass. For each of these four metrics, the top ranked model in the evaluation of prescribed fire treatment effects contained no prescribed fire effects, but did contain effects of strong year-to-year variation in populations. Models which predicted that fire effects differed depending on the season of fire received only limited support for each of the four metrics. Our results suggest that initial prescribed fires set during the early season will have similar impacts as late season fires on deer mouse populations, lodgepole chipmunk populations, and total small mammal biomass in Sierra Nevada mixed conifer forests.