The global expansion of mass schooling has greatly increased opportunities for low-income families, and governments have devoted much effort to equalising access and quality in education systems. Alongside regular schooling, the so-called shadow education system of private supplementary tutoring has grown rapidly across the world. The fact that rich families can purchase more and better quality shadow education undermines the achievements of increased equality of opportunities in formal schooling. Drawing on a mixed-methods study in Shanghai, China, the article shows how shadow education has offset school equalisation policies through differentiation of access and through sorting mechanisms. Shadow education occupies a space beyond strict government control in which privileged families and elite schools ignore and mediate the equalisation policies, seeking competitive advantages. Uneven access to shadow education and tracking within it shape, maintain, and exacerbate inequitable schooling experiences at individual and institutional levels.