This article describes operant conditioning methodologies that have been essential to furthering our understanding of infant learning processes. We discuss diverse procedures and assessments that have yielded useful information about prenatal, postnatal, neonatal, and infant learning, as well as preferences for various auditory, visual, kinesthetic, and tactile stimulation. In addition, the applicability of contingency-based operant procedures such as high-amplitude nonnutritive sucking, synchronized face-to-face reinforcement, conjugate reinforcement and discrimination training procedures for studying infant perception, memory, vocal conditioning, social referencing, attachment, and fears is presented. Also, methodologies such as yoked-control procedures that distinguish between the reinforcement contingencies effects and the eliciting effects of social stimuli like Motherese speech and adult vocal imitation are described as ways to further refine functional analyses of infant learning. Overall, we provide a framework toward establishing operant conditioning methodologies as essential research tools for understanding infant learning phenomena.