Ellen Jane Langer (/ˈlæŋər/; born March 25, 1947) is an American professor of psychology at Harvard University; in 1981, she became the first woman ever to be tenured in psychology at Harvard. Langer studies the illusion of control, decision-making, aging, and mindfulness theory. Her most influential work is Counterclockwise, published in 2009, which answers questions about aging from her research and interest in the particulars of aging across the nation.