This paper reviews trends, outcomes and issues in regulatory reform in OECD countries. First, it summarises the evidence on the evolution of regulatory environments and the economy-wide and sectoral effects of reforms (including privatisation) in both competitive and non-competitive industries in the past two decades. Turning to network industries, it then discusses the main policy issues raised by the need to adapt the regulation of the noncompetitive segments of these industries to increasing competition in liberalised markets. It focuses on four topics that dominate the debate over regulatory reform: i) the move from command-and-control to incentive-based regulatory approaches based on the removal of entry barriers in competitive markets, the adoption of price-cap mechanisms and the design of efficient and competitively-neutral charges for accessing the fixed networks of incumbents; ii) the pros and cons of structural measures such as privatisation, and vertical and horizontal ...