The purpose of this article is to draw a theoretical distinction between the notions of ‘social classes’ and ‘subaltern groups’ as defined in The Prison Notebooks by Antonio Gramsci. This distinction will involve a brief discussion about the notions of ‘social classes’ evolved by other key authors in the area, apart from Gramsci himself, such as Marx, D. Bensaïd, E. P. Thompson and N. Poulantzas, who, on this question, have close affinities with the ideas of Gramsci. Finally, I seek to make suggestions about how this distinction can be applied, together with some critical observations on ‘Subaltern Studies’ and some final considerations with regard to this article as a whole.