This article contributes to the philosophical debate on values in science by exploring how scientists themselves understand the proper role of moral, political, and social values in expert practice. I present findings from interviews with climate scientists who have participated as authors in the Intergovernmental Panel on Climate Change (IPCC). The climate scientists subscribe to the value-free ideal as a regulative ideal that applies both to the provision of knowledge to policymakers and how they engage with political issues in the public sphere. Yet their views on the moral responsibility of scientists and the aim of providing policy-relevant output challenge the value-free ideal. The article suggests ways in which their views can be relevant to the philosophical discussion.