Discovery of petroleum resources in Arctic waters and the rapid loss of sea ice raise concerns over environmental risks of oil development in Arctic waters. One of the biggest threats to the marine environment from offshore oil production is a large-scale oil spill, akin to Deepwater Horizon. The challenging operating conditions, lack of infrastructure and effective clean-up techniques in the Arctic conditions exacerbate the need to ensure robust regulation of petroleum activities in the region. Whereas national laws vary extensively across the Arctic States, international law does not offer a uniform approach to prevention of and response to oil spills. This paper examines the scope and application of the relevant treaties and argues that a regulatory gap exists in the prevention of oil spills and addressing the challenges of response in Arctic conditions. It further suggests that there is an increasing role for soft-law regional cooperation in addressing these gaps.