Dame Helen Alexander, who was married with three children, had been battling cancer for several years.
She was chairman of Incisive Media between October 2009 and December 2014 and played a key role in the development of the business, says the company.
Tim Weller, chairman of Incisive Media, said: “Helen was a wonderful, inspiring and compassionate woman. She was a great listener, warm and effective.
“It was an enormous privilege to work with her when she was chairman of Incisive Media and I will miss her tremendously.
“My thoughts are with her husband Tim and her children Nina, Greg and Leo at this very sad time.”
Dame Alexander began her career in publishing at Faber & Faber, before moving to the Economist Group in 1985, where she became managing director in 1993 before taking the helm in 1997.
Her career also included boardroom roles at Rolls-Royce, Centrica and Northern Foods.
Throughout her career, Dame Alexander was seen as a trailblazer for women in business. Alongside Sir Philip Hampton, she headed up the Hampton Alexander Review, which focused on boosting the role of women in senior business positions.
