James Alexander Mirrlees (born July 5 1936, Minnigaff , Scotland) is a Scottish economist and winner of the 1996 Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel.

Educated at the University of Edinburgh and Trinity College, Cambridge, he taught at both Oxford (1969-1995) and Cambridge (1995-). It was during his time at Oxford that he published the economic models and equations for which he would eventually be awarded his Nobel Prize. They centred around analysis of economic situations in which the information is asymmetrical or incomplete, determining the extent to which they should affect the optimal rate of saving in an economy. Among other results, they demonstrated the principles of "moral hazard" and "optimal income taxation" discussed in the books of William Vickrey. The methodology has since become the standard in the field.

Vickrey and Mirrlees shared the 1996 Nobel Prize for Economics "for their fundamental contributions to the economic theory of incentives under asymmetric information".

Mirrlees is currently Professor of Political Economy at the University of Cambridge, and a fellow of Trinity College, Cambridge.