© 2021 The Authors. Infant Mental Health Journal published by Wiley Periodicals LLC on behalf of Michigan Association for Infant Mental HealthThere is a lack of instruments assessing child–caregiver attachment relationships in early childhood to be used in attachment-based practice, in particular from a caregiver's perception, which is an important factor of clinical importance to take into account in parenting interventions targeting young children. Therefore, the 48-item Attachment Relationship Inventory—Caregiver Perception 2–5 years (ARI-CP 2–5) was developed. Survey data of 446 caregivers of 2- to 5-year-old children were collected, and a subsample of 83 caregivers participated in an observation study. Confirmatory factor analysis confirmed a four-factor structure of secure, avoidant, ambivalent, and disorganized attachment relationship. Indications of configural, metric, and scalar invariance were found for caregivers’ and children's sex, children's age, and population (clinical vs. general population). The four scales showed sufficient internal consistency and significant associations with children's psychopathology, caregivers’ general attachment representations, caregivers’ mind-mindedness, and population type. Moreover, preliminary evidence for convergent validity with observational attachment measures was found. It is concluded that the ARI-CP 2–5 is a valid instrument that can be used as part of the screening and assessment of insecure attachment relationships.