"In light of recent events, we've decided to stop operations of the TikTok app in Hong Kong," a spokesman told the BBC.
The company's exit from the city will come "within days," according to the Reuters news agency.
Facebook and Twitter said this week they were "pausing" co-operation with Hong Kong police over user information.
The short-form video app was launched by China-based ByteDance for users outside mainland China as part of a strategy to grow its global audience.
The tech company operates a similar short video sharing app in China called Douyin.