Scottish Secretary David Mundell is backing Michael Gove in the next round of the Conservative leadership contest
Mr Mundell said the Environment Secretary has a "strong track record of supporting Scottish interests".
Announcing his voting intention on Twitter, Mr Mundell wrote: "I will be voting for Michael Gove in the next round of the Tory Leadership Contest.
"Michael's track record in Government is of supporting Scottish interests and standing up for our United Kingdom."
Mr Mundell voted for Matt Hancock in the first ballot of leadership contenders earlier this week but the Health Secretary then withdrew from the race, after coming sixth.
The Scottish Secretary's announcement means he remains at odds with Scottish Conservative leader Ruth Davidson over who should become party leader, and therefore Prime Minister.
Ms Davidson has already backed Home Secretary Sajid Javid in the leadership race.
Ms Davidson said Mr Javid, the son of a Pakistani bus driver, "embodies the Conservative values of aspiration, education, opportunity, hard work and just reward".