PROJECT SUMMARY It is commonly believed that childhood obesity is caused by neglectful and inept parenting. Because of these stereotypes, parents of children with obesity are shamed by their families and dismissed by healthcare providers. This treatment is a form of stigma termed “stigma by association.” We hypothesize that stigma by association, and parents’ internalization of this stigma, harms parents' health, interferes with family relationships, and impacts children’s health. However, it is not possible to understand the effects of this form of stigma because there are no established measures of this concept. The objective of this R21 is to develop and validate a measure of parents’ experiences of stigma by association due to child obesity and parents’ internalization of this stigma. To accomplish this, we will complete the following specific aims: Aim 1. Develop the Stigma by Association due to Child Obesity (SACO) scale, a quantitative measure of parents’ experience of stigma by association and stigma internalization due to child obesity, and Aim 2. Test the psychometric properties of the SACO. We will also examine associations between the SACO scores and biopsychosocial measures of parent health, the parent-child relationship, and child health and healthcare utilization (Exploratory Aim). This project falls within the scope of NICHD’s Exploratory/Developmental Grant (R21) program, which fosters the development of novel scientific tools to advance behavioral and clinical research to improve the health of children and families. This project is conceptually innovative in its focus on stigma directed toward parents of children with obesity, which has received little attention despite our growing recognition of the harms of weight stigma. The development of the SACO is significant because it will allow for rigorous assessment of the prevalence of this form of stigma across diverse populations and the advancement of etiologic research to identify its impact on families. Ultimately, the SACO can be used to understand how intervention strategies and communication approaches affect parents' experiences of stigma and to identify family strengths and assets that promote resilience against this stigma. This knowledge is essential to develop health promotion approaches that minimize parent-directed stigma and support health and well-being for parents and children.