A deep understanding of the processes affecting the population dynamics of living organisms requires fine-scale analyses of basic demographic parameters such as stage-specific survival and growth rates. In this study we estimated survival, detection, and transition rates (growth) for different stages of the life cycle of a Knob-scaled Lizard of the genus Xenosaurus. We also examined potential sources of variation for these parameters by means of a multiple-model inference framework. Our capture–mark–recapture data revealed that survival rates were homogeneous among stage classes but markedly different between the rainy and dry seasons. Contrary to our expectation, survival probability was higher during dry months. Detection probability varied considerably among stage classes and through time. Consistent with theoretical predictions, the rate at which lizards moved from a particular stage class to the following (transition rates) varied among stage classes, with the fastest rates observed in yearlings and the slowest in adults. Also consistent with our predictions, we found a tendency toward faster transition rates during rainy months. We discuss the potential causes and implications of the patterns of variation observed in these key demographic parameters.