There is much optimism that the 2015 Conference of the Parties of the United Nations Framework Convention will yield an agreement on mitigation of climate change, to become effective in 2020. In this context, Bahrain represents a developing country with insufficient data to assess mitigation opportunities: its per capita carbon emissions rank among the world’s highest, yet there has been no research on the reduction potential of its rapidly growing transport sector. We examine this reduction potential and the costs of various mitigation measures and, further, explore barriers and the view of policymakers and experts. Potential benefits of combined mitigation scenarios are also identified based on their acceptability. We adopt a modified participatory method to develop the scenarios, using the long-range energy alternative planning (LEAP) modelling system, and find that an integrated policy approach can deliver a 23 % reduction in carbon dioxide emissions, costing 108 United States dollars per avoided metric tonne, with politically acceptable scenarios. Better performance, however, would require less acceptable approaches. These findings are significant for decision-making in Bahrain and other Gulf Cooperation Council countries; national target preparation and the setting of fuel economy standards should be begun promptly. We offer lessons to other developing countries on the timely regulation of technical specifications and numbers of passenger vehicles. Participatory approaches to the assessment of mitigation measures can advance environmentally effective, economically feasible and politically acceptable scenarios. The global community can use these results to provide necessary technical and financial assistance to developing countries.