David MacKay is a Professor in the Department of Physics at the University of Cambridge, and a Fellow of the Royal Society (FRS).

He studied Natural Sciences at Cambridge and then obtained his PhD in Computation and Neural Systems at Caltech - the California Institute of Technology. He returned to Cambridge as a Royal Society research fellow at Darwin College. He is internationally known for his research in machine learning, information theory, and communication systems, including the invention of Dasher, a software interface that enables efficient communication in any language with any muscle. He has taught Physics in Cambridge since 1995. Since 2005, he has devoted much of his time to public teaching about energy. He is a member of the World Economic Forum Global Agenda Council on Climate Change.

In October 2009 he was appointed Chief Scientific Advisor to the UK Department of Energy and Climate Change ("DECC").