Positive childhood experiences (PCEs), that occur within secure and nurturing social environments, are fundamental to healthy physical, social-emotional, and cognitive development. However, reliable measures of these experiences are not yet widely available. We used data from the Longitudinal Study of Australian Children (LSAC) to empirically represent and psychometrically evaluate 3 primary domains of PCEs defined within the Health Outcomes from Positive Experiences (HOPE) framework, specifically: 1) nurturing and supportive relationships; 2) safe and protective environments and; 3) constructive social engagement and connectedness.