This paper takes stock of the current debate around the informal sector and informal entrepreneurship. Informal entrepreneurship represents a worldwide characteristic of entrepreneurial activity, the main distinguishing feature of which is that it is operating outside the law. Since what is legal can vary considerably between countries, studies of entrepreneurship which exclude informal activity must be considered partial. Moreover, it can be argued that the distinction between formal and informal is not black and white but rather shades of grey. Although informal economic activity is often more prominent in developing countries and transition economies, it is by no means confined to them. There are parts of the UK, for example, where local economies are dependent upon informal employment and for many goods and services. More generally, much of the home-based economic activities, such as cleaning, painting and decorating and other services, are typically provided, at least partially, in the informal sector. As a consequence, it is difficult to argue against including informal activity as part of the study of entrepreneurship, and particularly where the entrepreneurial potential of an economy is being assessed.