The recent 2018 special report on climate change produced by the Intergovernmental Panel on Climate Change (IPCC) of the United Nations unsurprisingly revealed states’ continued failure to properly implement environmental law and meet their climate change pledges, thus bringing the world closer to a point of no return. Considering the imperfections of national environmental laws in most countries, alternative sources of law and normativity can be engaged to complement efforts in effecting social control and fostering compliance. Religious law is one such source, and where the environment is concerned, religious leaders worldwide have highlighted the existence of an environmental ‘law’ in their respective traditions. Logically then, religious law can help effect behavioural change in religious communities such that they can become more ‘pro-environment’. This paper analyzes how Islamic law – specifically Islamic environmental law – has been used in Singapore, Malaysia, and Indonesia for this purpose. It particularly examines and analyzes the dissemination of Islamic environmental law to Muslims in these jurisdictions through religious rulings (fatwa) and mosque sermons (khutbah). The paper then evaluates the challenges to Islamic environmental law by situating its operation in two important contexts: (1) the context of religion-state relations in Southeast Asia, and (2) psychological studies on pro-environment behaviours arguing that religion alone cannot motivate individuals to behave in a pro-environment manner. The paper concludes by reflecting on what these challenges mean for the search for solutions to our environmental predicaments, as well as prospects for further intellectual inquiry.