Twitter said on Thursday that Ali Rowghani has resigned as chief operating officer, effective Thursday.
The micro-blogging website said it did not intend to hire a replacement for Rowghani, whose operating responsibilities would be assumed by others in the management.
Rowghani, however, would continue to be an employee of the company and act as a strategic adviser to the chief executive.
Technology news website Re/code reported on Wednesday that Twitter was considering a shake-up in its top management, including a possible shift in the duties of Rowghani.
Chloe Sladden, Twitter's North America media boss, who reports to Rowghani, has been reorganizing her unit and she may be preparing to leave the company, the website added.
Twitter did not comment on Sladden in its filing on Thursday.
Twitter's first-quarter results in April revealed slowing momentum at the company that exuberant investors just six months ago had argued could one day match Facebook's scale.
Twitter's shares were little changed at $35.64 on the New York Stock Exchange on Thursday.