Given the relevance of caregivers' perceptions, cognitions, and emotions about their child's mental states for caregiving behavior and children's development, researchers from multiple theoretical perspectives have developed constructs to assess caregivers' cognitions, resulting in a large but scattered body of literature. In this article, we highlight the conceptual overlap among and uniqueness of six constructs assessing caregivers' cognitions about their child at 36 months and younger: infant intentionality, mental representations, mind-mindedness, parental embodied mentalizing, parental empathy, and parental reflective functioning. We define constructs, present approaches to measurement, and propose elements of importance that fall under the umbrella of caregivers' cognitions and that may be associated differentially with children's early cognitive and social-emotional development. We conclude with recommendations for researchers aiming to capture caregivers' cognitions about their child's mental states, whether focusing on one of the six reviewed constructs or on specific elements (e.g., awareness of the child's mind or accuracy of caregivers' perceptions of their child) under the umbrella of caregivers' cognitions.