State longitudinal data systems (SLDSs) promise a rich source of data for education research. SLDSs contain statewide student data that can be linked over time and to additional data sources for education management, reporting, improvement, and research, and ultimately for informing education policy and practice. Authored by Karen Levesque, Robert Fitzgerald, and Joy Pfeiffer of RTI International, this guide is intended for researchers who are familiar with research methods, but who are new to using SLDS data, are considering conducting SLDS research in a new state environment, or are expanding into new topic areas that can be explored using SLDS data. The guide also may be useful for state staff as background for interacting with researchers and may help state staff and researchers communicate across their two cultures. It highlights the opportunities and constraints that researchers may encounter in using state longitudinal data systems and offers approaches to addressing some common problems. The following are appended: (1) Sample High School Feedback Reports; (2) Characteristics of statewide student data systems, by state: 2009-2010; (3) The Family Education Rights and Privacy Act--guidance for reasonable methods and written agreements; and (4) Additional questions for confirming specific data availability.