This paper asks what implications the agreement to address the challenges of climate change from the 21st Conference of the Parties (COP21) might have for trade and investment policy in Commonwealth member countries. Whilst trade and investment are not directly mentioned in the Agreement, there are important elements of the trade agenda that should be pursued to take advantage of the opportunities presented by the coming green transition, as well as to protect against the downsides of unilateral climate action. The paper also asks more broadly how Commonwealth governments might support a mutually reinforcing relationship between trade and environmental regimes.