Kimberly Ellen Kagan (born 1972) is an American military historian. She heads the Institute for the Study of War and has taught at West Point, Yale, Georgetown University, and American University. Kagan has published in The Wall Street Journal, The New York Times, The Weekly Standard and elsewhere. She supported the 2007 troop surge in Iraq and has since advocated for an expanded and restructured American military campaign in Afghanistan. In 2009, she served on Afghanistan commander Gen. Stanley McChrystal's strategic assessment team.