This study examined selected parameters of two newly developed measures called AEPS-3 Ready-Set and Ready-Set Family Assessment of Children's Skills (FACS). Ready-Set is a school readiness measure designed to gather information from teachers or other professionals on children's kindergarten school readiness skills across important developmental areas. FACS is a companion measure developed to provide a simple way for parents to assess and report their child's skills across the same developmental areas addressed by Ready-Set. Montessori educators practicing in Florida and Idaho observed groups of preschool-age children and completed the Ready-Set assessment on selected children. In addition, selected children's parents completed the FACS designed to provide information about their child's skills across the same developmental areas targeted by Ready-Set. Analyses found a robust correlation between parents' and teachers' ratings on total area scores and more modest agreements on individual items. Teachers reported that they considered Ready-Set a user-friendly tool that provided relevant information on children's' readiness skills. In addition, teachers reported they would use Ready-Set again, as well as recommend its use to co-workers. This study has implications for assessing school readiness of children from both teachers and parents.