This chapter analyses the meaning, legal implications, and policy consequences of Decentralised Finance (‘DeFi’). Decentralisation has the potential to undermine traditional forms of accountability and erode the effectiveness of traditional financial regulation and enforcement. At the same time, where parts of financial services are decentralised, there will be a reconcentration in a different (but possibly less regulated, less visible, and less transparent) part of the financial services chain. DeFi regulation could and should focus on this reconcentrated portion to ensure effective oversight and risk control. In fact, DeFi requires regulation in order to achieve its core objective of decentralisation. Furthermore, DeFi may further the idea of ‘embedded regulation’– building regulatory approaches into the design of decentralised infrastructure, potentially decentralising both finance and its regulation in the ultimate expression of RegTech.