The SLDS Early Childhood Planning Guide is a supplemental resource for the SLDS Early Childhood Self-Assessment Tool. The Self-Assessment Tool was created to help states assess their needs as they integrate EC data into an EC data system and the P-20W SLDS. The sections of the Planning Guide align with the sections of the Self-Assessment Tool (see Figure 1), and offer practical suggestions and resources for each step in the overall process of integrating EC data into an SLDS. The states that collaborated on this document are in different stages of incorporating EC data into the SLDS and have generously shared their experiences and resources to help all agencies and programs benefit from lessons learned. The first of its kind, this document is a comprehensive guide for states that are planning and developing systems that will integrate EC into their SLDS and have identified a need from their self-assessment. (author abstract)