The purpose of test directions is to familiarize examinees with a test so that they respond to items in the manner intended. However, changes in educational measurement as well as the U.S. student population present new challenges to test directions and increase the impact that differential familiarity could have on the validity of test score interpretations. This article reviews the literature on best practices for the development of test directions as well as documenting differences in test familiarity for culturally and linguistically diverse students that could be addressed with test directions and practice. The literature indicates that choice of practice items and feedback are critical in the design of test directions and that more extensive practice opportunities may be required to reduce group differences in test familiarity. As increasingly complex and rich item formats are introduced in next-generation assessments, test directions become a critical part of test design and validity.