["European Journal of Education, Volume 61, Issue 2, June 2026. ", "\nABSTRACT\nSince the introduction of the maximally maintained inequality (MMI) hypothesis, the effect of educational expansion on inequality of educational opportunity (IEO) has been widely debated, with empirical studies producing conflicting results. Using data from the European Social Survey (ESS), this study examines whether the effect of educational expansion is context‐dependent by focusing on four macro‐level indicators derived from the choice dimension (educational returns and costs) and the capital dimension (economic capital inequality and cultural capital inequality). The results show that, at the upper secondary level, the effect of educational expansion varies significantly across social contexts, with educational returns, economic capital inequality and cultural capital inequality exerting significant moderating effects. For higher education, educational expansion is overall associated with lower IEO, but this association does not vary significantly across the four macro‐level indicators. This study provides empirical evidence explaining why the effects of educational expansion are context‐dependent rather than unidirectional.\n"]