As “market referees”, regulators contribute to the delivery of essential public utilities. Their organisational culture, behaviour and governance are important factors in how regulators, and the sectors they oversee, perform. This report uses the OECD Performance Assessment Framework for Economic Regulators (PAFER) to assess both the internal and external governance of Peru's Supervisory Agency for Private Investment in Telecommunications (OSIPTEL). The review acknowledges OSIPTEL's achievements and good practices, analyses the key drivers of its performance, and proposes an integrated reform package to help the regulator prepare for the future.