Theory chief executive Andrew Rosen is stepping down on 1 April, after more than two decades in the role.
Rosen, who founded the brand in 1997, will continue as an adviser to the New York-based men’s and women’s contemporary fashion brand.
Theory chief operating officer Dinesh Tandon will take on the role of CEO.
Tandon joined in 2013 as CEO of the Greater China and south-east Asia market, based in Hong Kong. He became COO in New York in 2017.
Theory was bought by retail company Fast Retailing, which owns Uniqlo, J Brand, Comptoir des Cotonniers, GY and Princesse Tam-Tam in 2009.
Theory had 461 stores worldwide, including franchise shops, as of 30 November.
In the UK, Theory is stocked in Harvey Nichols and has its own standalone store in Marylebone in central London.
Tadashi Yanai, chairman and president and CEO of Fast Retailing, said: “I wish to thank Andrew for his significant contributions to Theory and the Fast Retailing over the past 10 years. I am pleased to see this succession in leadership as Andrew begins a new phase of his career.”
Rosen said: “My new role will allow me to provide mentorship and advice to the team at Theory, and will also give me an opportunity to pursue other interests and passions within and beyond the industry.”