Katherine Williams Phillips (March 4, 1972 – January 15, 2020) was an American business theorist and the Reuben Mark Professor of Organizational Character at Columbia University's Business School. She headed the Sanford C. Bernstein & Co. Center for Leadership and Ethics at Columbia, and was Senior Vice Dean.

Born Katherine Y. Williams to Adolph Williams and Amelia (Rogers), Phillips was the youngest of six siblings. She grew up in a black Chicago neighborhood, and in the third grade, was chosen to attend a nearly all-white magnet school where she was one of the few black students. She graduated from the University of Illinois at Urbana-Champaign and earned a PhD from Stanford. She was a tenured professor at both the Kellogg School of Management at Northwestern University and the Columbia Business School. Phillips was known for her research into diversity in the workplace, demonstrating that diversity on teams leads to greater innovation and creativity. She was a Senior Vice dean at Columbia and had published collaborations with other faculty on Diversity and other topics. She was its Reuben Mark professor of organizational character. Her latest position was as the director of its Sanford C. Bernstein & Co. Center for Leadership and Ethics.

She married fellow Stanford graduate and Columbia Business School professor Damon Phillips, the Lambert Family Professor of Social Enterprise at Columbia. Phillips was a three-time All American in Track and Field at the University of Illinois Urbana Champaign where she competed in the 400 m dash, long jump and relays.

Named one of the "Top 40 Business School Professors Under the Age of 40" by Poets and Quants in 2011, Phillips was also an Academy of Management Fellow.

Phillips died of breast cancer on January 15, 2020, at age 47. Phillips is survived by her husband and their two daughters.