The relationship between trade liberalization and informal activity has not received the attention, whether theoretical or empirical, that it may deserve. The conventional view posits that trade liberalization would cause a rise in informality. This paper uses three different data sets to assess the sign of the relationship. Empirical results provide a mixed picture. Macro-founded data tend to produce results supporting the conventional view; micro-founded data do not. Empirical results also suggest that while informal output increases with deeper trade liberalization, informal employment falls.