In this chapter, we make a first attempt at exploring the intersection where sustainable finance, fintech, and competition law and policy meet. We find that fintech can ensure that sustainable finance goes beyond greenwishing and avoids greenwashing, while at the same time supporting increasing competition. Fintech has this potential because it can enable better reporting, monitoring, data collection, supply chain transparency, crowdfunding, and microfinancing – all of which support true sustainability-related financing – and it can increase innovation, disrupt markets, help reduce barriers to entry and expansion, and challenge incumbents’ market power, thereby safeguarding and promoting healthy competition for sustainability solutions. In other words, fintech can help democratise sustainable finance. In order for this potential to be realised, policymakers must design regulation at an optimal level, balancing high standards with regard to sustainability with competition, whereas competition law enforcers must ensure competition in sustainability solutions is safeguarded by enforcing competition rules in a manner that takes into account the impact of businesses’ market conduct on parameters of sustainability such as climate change, biodiversity, and social justice. Strong enforcement of competition rules ought also to assist in avoiding the two ways we identify in which increased presence of fintech in sustainable finance would be problematic, namely by increasing possibilities for collusion or information exchange and by further strengthening the market power of BigTech companies