This article contributes to the knowledge on organizational stratification in higher education by exploring its financial dimension in 21 European countries over the period 2013–2017. Cross-country differences in the inequality of revenues among higher education institutions are considerable. Decomposing inequality indices shows that they are related to the various degrees of institutional diversity in size, research activity, and subject specialization. Financial stratification is higher in countries where revenues are more unequally distributed among universities involved in research, especially those with a broad disciplinary focus. This inequality is in turn driven by the role of third-party funding in higher education financing.