This article examines major unresolved challenges in the assessment of pre-K-grade 12 multilingual students in US public schools. The ethnic educator approach advocates for a change of paradigms in assessment, one that abandons the medical model to incorporate socio-constructivist theoretical perspectives and pluralistic and progressive social justice ideologies that respect, value, and celebrate the cultural-linguistic diversity of bilingual/multilingual students. Past, present, and future challenges in the assessment of multilingual students are discussed, emphasizing the need: (a) for teacher preparation programs to include training in classroom-based assessments, (b) to use the students' first language for linking assessment to academic competence across content areas, and (c) to use classroom-based assessments representing the students' cultural and socio-economic status (SES) backgrounds. Some recommendations for future research on best practices in the assessment of bilingual/multilingual students are made.