IDEO is an international design and innovation consultancy founded in Palo Alto, California, United States with other locations in San Francisco, Chicago, New York, Boston, London, Munich, Shanghai, Singapore, Mumbai, Seoul, and Tokyo. The company helps design products, services, environments, and digital experiences. Additionally, the company has become increasingly involved in management consulting and organizational design.

IDEO was formed in 1991 by a merger of three established design firms: David Kelley Design (founded by David Kelley, who is also a professor at Stanford University), ID Two (founded by Britain's Bill Moggridge), and Matrix Product Design (founded by Mike Nuttall). Office-furniture maker Steelcase had owned a majority stake in the firm, but began divesting its shares through a five-year management buy-back program in 2007. The founders of the predecessor companies are still involved in the firm. The current CEO is Tim Brown.

The firm employs over 550 people in the disciplines of human factors, mechanical, electrical and software engineering, industrial design, interaction design, and communication design. IDEO has worked on thousands of projects for a large number of clients in the consumer food and beverage, retail, computer, medical, furniture, toy, office, and automotive industries. Notable examples are Apple's first mouse, Microsoft's second mouse, the Palm V PDA, and Steelcase's Leap chair. Major clients (as of 2004) included Procter & Gamble, PepsiCo, Microsoft, Eli Lilly, Ford, and Steelcase.