In recent years, the world has witnessed a soaring inflow of capital into sustainable investment. This is particularly so following the devastating COVID-19 pandemic. However, while a growing amount of literature has been deliberating debt financing in sustainable investment, less ink has been spilt on equity financing in this area, and even less scholarship has explored the role of government and law in supporting sustainable venture capital (‘VC’) funds. This paper proposes a dualist approach towards facilitating the development of sustainable VC funds encompassing a contractarian strategy with government support. The contractarian approach includes effective contracting covering the entire VC cycle in sustainable investment. It aims to provide strong incentives for all participants, ranging from investors, entrepreneurs and fund managers, to credit-rating agencies and evaluation firms. In the same vein, this paper seeks to craft a role for regulators that facilitates the simultaneous availability of several factors in a sustainable VC cycle (i.e., fund raising, investment and exit). In the fund-raising stage, governments can play an active role by expanding the source of financing for sustainable VC funds and enacting detailed and targeted legislation. In the VC investment stage, sustainable VC funds should make full use of their strong corporate governance rights and monitoring tasks to ensure that start-ups deliver on their sustainable promises. In the exit stage, a specialised sustainability board is strongly recommended to offer viable exit options, together with greater standardisation and comparability in sustainability information disclosure, and regulatory support for trustworthy sustainable impact rating agencies to sustain investor confidence.