In developing nations, formal workers tend to be more experienced, more educated, and earn more than informal workers. These facts are often interpreted as evidence that low-skill workers face barriers to entry into the formal sector. Yet, there is little empirical evidence that such barriers are important. This paper describes a model where, in equilibrium, the characteristics of formal and informal workers differ systematically, even though labor markets are perfectly competitive. The informal sector emphasizes low-skill work, as in the data, because informal managers have access to less outside financing, and choose to substitute low-skill labor for physical capital.