This systematic review examined the research evidence for interventions used by occupational therapists to improve cognitive development in children from birth to age 5. Thirteen studies met the inclusion criteria and were reviewed by three teams of two people. From the selected articles, which described Level I and IV studies, two general categories emerged: (1) developmental interventions and (2) joint attention interventions. Developmental interventions occurred in neonatal intensive care units, home, child care centers, and preschools. Synthesis of the articles indicates that developmental interventions result in gains in early cognitive development (e.g., infant and preschool age) with inconclusive evidence for gains through school age. Educating parents of preterm infants to be more sensitive to their child’s needs and more responsive in interactions increased cognitive outcomes and joint attention. Interventions using joint attention enhanced generalization to novel situations and increased play, language, and social interactions in preschoolers with autism. Further studies that describe intervention strategies used to enhance cognitive functioning to promote preliteracy skills such as joint attention, imitation, memory, problem solving, and decision making and are conducted by occupational therapists are needed.