Culturally relevant assessments (CRA) account for multiple socio-cultural identities, experiences, and values that mediate how students know, think, and respond to test items. Given the diversity of modern classrooms, it is critical that education researchers and practitioners understand and strive to implement CRA practices. This systematic review and synthesis of 20 empirical studies demonstrate the positive impact of CRA on culturally and linguistically diverse learners' understanding of and performance on assessments and highlights 12 emerging practices that can inform assessment design and development. While most of the studies reviewed focus on classroom practices, findings are discussed in view of their significance for large-scale assessment and areas of need for future or replication of studies.