Against the backdrop of the English reception of Locke’s Essay, stands a little-known philosophical dispute between two seventeenth-century women writers: Mary Astell (1666-1731) and Damaris Cudworth Masham (1659-1708). On the basis of their brief but heated exchange, Astell and Masham are typically regarded as philosophical adversaries: Astell a disciple of the occasionalist John Norris, and Masham a devout Lockean. In this paper, I argue that although there are many respects in which Astell and Masham are radically opposed, the two women also have a surprising amount in common. Rather than interpret their ideas solely in relation to the ‘canonical’ philosophies of the time – Lockean empiricism and Malebranchean occasionalism – I examine the ways in which Astell and Masham are influenced by the metaphysical theories of the Cambridge Platonists, Ralph Cudworth and Henry More. On this basis, I argue that a remarkably similar theological approach underlies the metaphysical and feminist arguments of Astell and Masham.