Reinforcement learning, the process by which an organism flexibly adapts behavior in response to reward and punishment, is vital for the proper execution of everyday behaviors, and its dysfunction has been implicated in a wide variety of mental disorders. Here, we use computational trial-by-trial analysis of data of female rats performing a probabilistic reward learning task and demonstrate that core computational processes underlying value-based decision making fluctuate across the estrous cycle, providing a neuroendocrine substrate by which gonadal hormones may influence adaptive behavior.