Although the first three years of a child's life are a distinct developmental period, little information is available about the specific knowledge, skills, and other attributes (that is, competencies) that are essential to the practice of teaching and caring for infants and toddlers (I/T) and are needed to support optimal development. Identifying the competencies essential to a given profession may help to provide a common language and lens for assessing job performance and provide a clear structure for professional growth and development. The goal of this review was to examine what is known about the links between I/T teacher or caregiver competencies and outcomes in several areas (child, family, teacher/caregiver, classroom, and/or program). Specifically, the authors aimed to answer the following research questions: (1) What competencies of I/T teachers and caregivers have been examined in the literature?; (2) What does evidence say about associations between I/T teacher and caregiver competencies and child, family, teacher/caregiver, classroom, and/or program outcomes?; and (3) Where are the gaps in the knowledge base pertaining to connections between I/T teacher/caregiver competencies and outcomes? This review suggests that the knowledge base pertaining specifically to links between I/T teacher or caregiver competencies and outcomes is currently limited in scope. Although many studies focus on describing competencies, the literature search yielded only 30 studies conducted in the United States in or after 2008 that examined associations between I/T teacher or caregiver competencies and outcomes. Although there is variation in the competencies and outcomes addressed in the studies reviewed, there are several gaps in the recent knowledge base pertaining to connections between teacher/caregiver competencies and outcomes: (1) The available research specific to I/T teachers and caregivers in group settings does not yet fully support the content included in existing competency frameworks targeted to this population; and (2) Much of the existing literature simultaneously examines the contributions of multiple competencies within a particular domain (e.g., a combination of knowledge, skills, or other attributes that support children's socioemotional development) to outcomes.