Bytedance Inc. is considering setting up a global headquarters for its hit video-sharing app TikTok outside of China, part of continuing efforts to shake off its Chinese image, people familiar with the company said.

Singapore is one city being considered, the people said. Other possible locations include London and Dublin, with no American cities on the shortlist, one person said. TikTok currently doesn’t have a headquarters, although its most-senior executive is based in Shanghai and its main office, which runs U.S. operations,...