Deloitte Touche Tohmatsu Limited /dəˈlɔɪt ˈtuːʃ toʊˈmɑːtsuː/, commonly referred to as Deloitte, is a multinational professional services firm headquartered in New York City in the United States.

Deloitte is one of the "Big Four" and the second largest professional services network in the world by revenue and the largest by the number of professionals. Deloitte provides audit, tax, consulting, enterprise risk and financial advisory services with more than 225,400 professionals globally. In FY 2015, earned a record $35.2 billion USD in revenues.