This paper uses a coalition formation model to explore how equity considerations affect countries’ cooperation on global environmental issues, e.g. on climate change. When developing countries are exempted from obligations to reduce their emissions, I find that opening them for abatement projects financed by industrialized countries changes the incentives to cooperate in a way which can increase emissions and decrease welfare. Equity- concerns in industrialized countries regarding the difference between their per capita emission levels and those of developing countries lead to increased abatement but do not qualitatively change the incentives to cooperate. Inequality-aversion with respect to differences to abatement targets across industrialized countries generally induces larger coalition sizes and stricter abatement. Here, the inclusion of developing countries improves upon the prospects of cooperation.