The effect of body temperature on the learning of Lashley mazes I and II was studied with the desert iguana, Dipsosaurus dorsalis. Indices of learning were error scores, number of trials to criterion, and running time. Four temperature groups were studied. Lizards trained at 22 °C did not exceed chance levels after 125 trials. A 27 °C and a 32 °C group successfully learned both mazes with fewer errors and less trials in the higher temperature group. Temperature coefficients for these two temperature groups were 3·1 on maze I and 2·3 on maze II. A second 32 °C group trained only on maze II did not differ significantly in trials and error scores from the 32 °C group experienced on maze I. However, variability within the experimentally naive group was less than that of the experienced groups. Results of this study indicate that body temperature is an important parameter of learning in heliothermic lizards.