Despite being one of the most important means to obtain commissions, explore in design terms and develop design quality, architectural competitions are an extremely controversial practice. Nevertheless, they are increasingly adopted within the European procurement law, to the point that exploring and understanding their debated issues is essential to improve their effectiveness. We use a paradox lens to open up managerial insights and to develop a theory of architectural competitions’ paradoxes. We propose a set of paradoxes and managerial implications for architects and clients/juries with regard to each competition phase: programming, selection and shortlist, design of the proposals, and jury decision making