Implementation of the Joint Comprehensive Plan of Action (JCPOA) in January 2016 has opened the door to foreign investment in Iran’s oil and gas sector and laid the groundwork for an end to the country’s economic isolation. Foreign companies entering Iran’s oil and gas sector nonetheless face a high degree of uncertainty and a challenging operating environment. The most salient risks for oil and gas companies broadly fall into two categories. Firstly, remaining non-nuclear sanctions present businesses with a substantial compliance burden. There are now more than 200 Iranian entities that are blacklisted by the US, many of which operate in the oil and gas sector. Foreign companies that do business with them – even if indirectly – risk severe fines or exclusion from the US financial system.