Constitutional structures shape politicians’ behaviour and hence policy outcomes through the different incentives schemes that they generate. In this paper we analyse these mechanisms in parliamentary and presidential systems. The comparison is carried out by analysing how the two systems may select the efficient policy in the presence of asymmetric information. Presidential and parliamentary systems differ in that the policy proposed by the executive in the parliamentary system is confidence‐dependent and observable. The main findings suggest that the parliament responds better to the incentive scheme in the presidential system due to the lower uncertainty faced by legislators over their term limit. However, the parliamentary system generates a more efficient behaviour of the executive due to selection and disciplining effects.