Nobuyuki Idei (出井 伸之, Idei Nobuyuki; born November 22, 1937) is a Japanese businessman. He was chairman and group chief executive officer of Sony Corporation until 7 March 2005. He is a director of General Motors, Baidu, Yoshimoto Kogyo and Nestlé.
After a stroke sidelined former chairman Akio Morita, Sony CEO and new chairman Norio Ohga selected Idei to be the next president, a choice that raised eyebrows at Sony. His sweeping reorganizations of the company included trimming the board of directors from 38 members dominated by company management to 10 with a substantial presence of outsiders. Already perceived as the company's driving force, Idei was formally named co-CEO in 1998 and sole CEO in 1999. In 2000, while Ohga remained chairman of the board, Idei became executive chairman and Kunitake Andō became president.
In 2003, on Ohga's retirement, Idei became the sole chairman, and the title of chief executive officer was altered to group chief executive officer. On March 7, 2005, it was announced that Idei would be succeeded on June 22 by Sir Howard Stringer.
On February 5, 2015 Idei retired from Accenture's board of directors.