B. Kevin Turner (born 1965) is an American businessman and investor who is the chairman of Zayo Group and the vice chairman of Albertsons/Safeway Inc.

During his nearly 20 years at Walmart, Turner rose through the ranks from a store cashier to become the company's global CIO, then CEO of Sam's Club, a $37 billion division of Walmart. Turner was the chief operating officer of Microsoft from 2005 to 2016. From 2016 to 2017, he was the vice chairman of Citadel LLC and CEO of Citadel Securities.

As Microsoft COO, Turner led the company's global sales, marketing, and services organization. He also managed Microsoft's partner channels and corporate support functions, including information technology, licensing, pricing, and operations. His organization included more than 70,000 employees in more than 190 countries. Turner remained through the transitions of Bill Gates, Steve Ballmer, and Satya Nadella.

Turner grew up in Stratford, Oklahoma. In 1987, Turner earned a Bachelor of Science in business administration with a concentration in management from East Central University in Ada, Oklahoma, where he was a member of the Pi Kappa Alpha fraternity. During his college years, he worked full-time as a cashier at Walmart.

Turner worked nearly 20 years at Walmart. He began working as a cashier in 1985 in his hometown of Ada, Oklahoma. While attending college, he rose through the store ranks, to customer service manager, housewares department manager and head office cashier. After several promotions, Turner found himself in the auditing department, where he came into contact with Sam Walton. On Walton's advice, Turner joined the company's information systems division, where he worked his way through a succession of jobs: business analyst, strategy manager, director, and then assistant CIO. In 1995, at the age of 29, Turner became Walmart's youngest corporate vice president and officer. In 1997, Turner became the recipient of the first "Sam M. Walton – Entrepreneur of the Year" award, the highest honor given at Walmart, voted on by the Walton Family.

In February 2000, 34-year-old Turner became the chief information officer of Walmart, after his boss Randy Mott left for Dell. He oversaw Walmart's information technology and worldwide data-tracking system. The division consisted of over 2,000 employees in Bentonville, Arkansas. He led the team that developed retail-specific applications such as Retail Link at Walmart. During his tenure, Turner was one of the world's largest corporate buyers of technology, and directed the technology strategy of a company renowned for its deft use of computing to streamline everything from global procurement to neighborhood shopping trends.

In 2002, Turner replaced Tom Grimm as the president and chief executive officer of the Walmart-owned retailer Sam's Club, which had over 46 million members and over US$37.1 billion in annual sales. In addition to his role at Sam's Club, he was also a member of the executive committee at Walmart. Under Turner, Sam's Club focused on lowering prices to win over small-business customers. In his last fiscal year as CEO, Sam's Club turned in 5.8 percent sales growth at stores open at least a year, nearly double the 2.9 percent sales growth at U.S. Walmart stores. As CEO, Turner improved the performance of the warehouse clubs and closed the gap with Costco. Turner was the president and CEO of Sam's Club until he left for Microsoft in 2005. After his departure for Microsoft, Sam's Club named Doug McMillon as its CEO.

In 2005, Turner was approached by Microsoft co-founder Bill Gates and CEO Steve Ballmer about overseeing the company's worldwide sales, marketing, services, and internal IT operations organization. He had worked with Gates and Ballmer during his time as CIO of Walmart. Turner accepted the offer and moved his wife and three children to Washington state where, in September 2005, he became the chief operating officer of Microsoft (the previous COO, Rick Belluzzo, had left the company in 2002 and no replacement had been hired).