This review protocol guides the review of research that informs the What Works Clearinghouse (WWC) "Preparing Young Children for School" practice guide and related intervention reports. The review protocol is used in conjunction with version 4.1 of the "WWC Standards Handbook" and "WWC Procedures Handbook." The new practice guide, "Preparing Young Children for School," addresses the topic of school readiness by focusing on preparing children for success in kindergarten and Grade 1. This guide will address interventions in early literacy, language, mathematics, social-emotional learning, and self-regulation. This broad focus is intended to encompass the core areas in school-readiness skills that are necessary to support children's success in elementary school and beyond. Numerous studies have documented significant and positive relationships between children's academic, emotional, and social skills at entry to kindergarten and their future achievement across a broad range of outcomes (National Early Literacy Panel, 2008; NICHD Early Child Care Research Network, 2005; Duncan et al., 2007).