In this paper, I discuss Hegel’s influential reading of Spinoza as a kind of idealist. I begin with a brief overview of Spinoza’s doctrines of substance, mode, and attributes. I then turn to Hegel’s arguments that Spinoza is an acosmicist (someone who denies the existence of finite individuals) and that Spinoza’s attribute of thought becomes the sole fundamental attribute. Underlying both criticisms is Hegel’s charge that Spinoza cannot consistently affirm his doctrine of substance and his doctrines of attribute and mode pluralism. In conclusion, I discuss the legacy of Hegel’s idealist reading.