The American Academy of Pediatrics recommends autism spectrum disorder screening at the 18- and 24-month well-child visits. However, despite widespread toddler screening, many children are not diagnosed until school age, and delayed diagnosis is more common among low-income and minority children. Offering autism spectrum disorder screening at preschool well-child checks might reduce disparities and lower the overall age of diagnosis and service initiation. However, screening tools that span the preschool ages and are tailored for primary care are needed.