Infant and early childhood mental health practices can be supported by policies and professional standards of care that foster the healthy development of young children. Policies that support infants and toddlers include those that strengthen their families to provide a family environment that promotes mental wellness. Policy issues for infants, toddlers, and young children have come to the forefront of thinking as children need a "voice" to advocate for their support and care. This article (a) highlights several important policy areas that support the social-emotional development of very young children and (b) gives examples of current policy accomplishments and challenges. The article offers a policy agenda to promote the mental health of infants and young children and suggests ways that psychologists can engage with policymakers to promote policies that foster infant mental health, including contributing to the knowledge base that informs policy decisions, educating the public and policymakers about early childhood development and mental wellness, forming community partnerships to identify and address infant mental health risks, and participating in the development of policy recommendations that improve access to evidence-based practices in infant mental health.