Early childhood development focuses on physical well-being, the development of motor skills and social interaction patterns, and the attainment of specific cognitive and communication skills. Developmental delay occurs when children are slow to achieve expected age-related norms for specific skills and may suggest underlying disease states. Developmental disabilities tend to be chronic conditions that affect social, physical, or cognitive development; these are reported in about 9% of children. Early intervention improves developmental outcomes with the potential for immediate and lasting effects. The American Academy of Pediatrics recommends developmental surveillance at every well-child visit, using a validated developmental screening tool during the 9-, 18-, 24-, and 30-month well-child visits. The US Preventive Services Task Force found insufficient evidence to support universal developmental screening for autism spectrum disorder or speech and language disorders at these ages. Family physicians should use their best judgment when deciding whether to implement universal developmental screening. Numerous screening tools are available with comparable sensitivity and specificity profiles at varying costs. For any child with developmental concerns, referral for diagnostic evaluation is warranted with access supported by federal law. Children younger than 3 years should be referred to early intervention services. Children 3 years and older are typically referred to school-based programs, although they may not be available to children in private schools without access to these resources. Chromosomal microarray testing or exome sequencing is recommended for children who have developmental disabilities without an explainable cause. Continued surveillance and/or screening is warranted at future appointments.