The first three years of a child’s life are a distinct developmental period, characterized by rapid brain development, reliance on relationships with adults, and extreme responsiveness to environmental variation. Identifying the competencies (i.e., knowledge, skills, and other attributes) essential to infant and toddler (I/T) teaching and caregiving may offer a common language and lens for assessing job performance and provide a clear structure for professional growth and development. In this compendium, we highlight measures that can be used to assess the competencies of I/T teachers and caregivers who work in group care settings (i.e., centers and family child care homes).