The economist Adam Smith was the first to come up with the hypothesis that a firm’s aim is always to maximise profits. However, in recent decades, economists have questioned the reasoning behind Smith’s neo-classical theory of the firm, and have put forward their own alternatives. This essay will begin with a discussion of what, exactly, the neo-classical theory is, in which I will define the theory, and demonstrate how it works, before moving on to a discussion of its shortcomings. Following this I will go on to explain the reasoning behind criticism of the neo-classical theory, and just why other economists were, and still are compelled to come up with alternatives.