This conceptual article explains how school counselors can increase awareness of size discrimination and address sizeist attitudes and biases in U.S. schools. Sizeism can begin in early childhood and continue into young adulthood, with damaging effects on student wellness. Sizeist biases in society are reflected in school systems. We suggest actions school counselors can take to promote equity in education for students of size, including implementing size-inclusive prevention strategies within a comprehensive school counseling program.