This article is adapted from "Linking Sensory Integration and Mental Health: Nurturing Self-Regulation in Infants and Young Children--A thoroughly revised and updated version of Sensory Integration and Self-Regulation in Infants and Toddlers" (ZERO TO THREE, 2022). This book was written for a broad multidisciplinary audience of service providers, researchers, and policymakers serving infants, young children, and their families. This edition has been expanded to highlight the intersection of sensory processing, sensory processing disorders, and infant and early childhood mental health (IECMH). Parents and family members may also find the contents helpful in understanding and caring for their child with sensory, self-regulatory, and social-emotional challenges in ways that will also enhance their relationships and family life. [This article was written with consultation and contributions from Marie E. Anzalone.]