This paper presents two studies outlining the development and validation of a new parent- and adolescent-report measure of the parent-adolescent relationship: the Parent-Adolescent Relationship Scale (PARS). Study 1 involved an exploratory factor analysis on a sample of 256 parents of adolescents aged 11-18 years. Results produced a 21-item measure comprising three subscales, Connectedness, Shared Activities, and Hostility, each with high factor loadings (> .60), strong internal consistency (H index = .84 to .91 for different age groups) and test-retest reliability (r = .73 to .84). Convergent validity was established via correlations between the PARS and established parent-adolescent relationship and parenting measures. Discriminant validity was shown via no association between the PARS and a technology use measure. Study 2 involved confirmatory factor analysis with a second sample of parents of adolescents, along with validation of adolescent and emerging adult versions. Equivalence of the models across the three versions was also assessed. Study 2 provided further support for the 3-factor structure, demonstrating configural, metric, and scalar invariance across the three final 15-item self-report versions: parent, adolescent, and emerging adult. Results show the PARS is a potentially valuable tool for assessing the quality of the parent-adolescent relationship. (PsycInfo Database Record (c) 2021 APA, all rights reserved).