McKinsey & Company is an American multinational strategy and management consulting firm that offers professional services to corporations, governments, and other organizations. Founded in 1926 by James O. McKinsey, McKinsey is the oldest and largest of the "Big Three" management consultancies (MBB). The firm mainly focuses on the finances and operations of their clients.

James Oscar McKinsey was an American accountant, management consultant, professor of accounting at the University of Chicago, and founder of McKinsey & Company.