Brent Callinicos is stepping down as Uber Technologies Inc.’s chief financial officer after helping spearhead the car-hailing service’s fastest years of growth.

Uber Chief Executive Travis Kalanick shared the news of Mr. Callinicos’s departure with investors Monday in an email reviewed by The Wall Street Journal. Mr. Callinicos will stay on as an adviser to Uber, while no replacement has been named, Mr. Kalanick told investors.

“Almost...