This article presents a detailed description of PESSOA - Portuguese Economy Structural Small Open Analytical model. PESSOA is a dynamic general equilibrium model that can be applied to any small economy integrated in a monetary union. The main theoretical reference behind its structure is Kumhof, Muir, Mursula, and Laxton (2010). The model features non-Ricardian characteristics, a multi-sectoral production structure, imperfect market competition, and a number of nominal, real, and financial rigidities. PESSOA has been calibrated to match Portuguese and euro area data and used to illustrate a number of key macroeconomic issues, ranging from the effects of structural reforms to alternative fiscal policy options.