Stuart Anderson, a long-time supporter of the outgoing Prime Minister, said the Foreign Secretary would carry on with the Government's investment in the city.
Meanwhile fellow MP Suzanne Webb revealed her support for Ms Truss, who looks increasingly likely to become the next Prime Minister ahead of Rishi Sunak.
It marks the first time both politicians have been able to declare their support for the candidate publicly, with the two prevented from doing so as Government whips.
Mr Anderson, who represents Wolverhampton South West, said he was backing the South West Norfolk MP after her pledges to cut taxes and boost defence spending.
"I know both candidates really well, they are two good candidates, however there's certain things I strongly believe in – lowering taxes to try to boost the economy, which is core to what Liz is doing," he said.
"I've spent two years on the Defence Sub-Committee (and I know how important) raising defence spending to three per cent of GDP which I know Liz has committed to.
"And I've spoken to her as well because Boris was very supportive of Wolverhampton, he really invested heavily into it and believed in levelling up and I'm told this would continue – she sees Wolverhampton as very important for the levelling up agenda."
Mr Anderson said he had voted for Ms Truss during the leadership votes in Parliament but had to stay neutral publicly, but this requirement has been removed as the vote has gone to the membership, leading him to declare straight away.
The MP added his choice was about choosing what was "right for Wolverhampton and the country".
Meanwhile Stourbridge MP Suzanne Webb added: "My view is Liz Truss is the best person to meet the challenges we face around the cost of living, Russian aggression and getting the economy back on track.
"I worked with her at the Department for International Trade and Women and Equalities where I was her Parliamentary Private Secretary. She is capable and experienced, works incredibly hard and gets the job done.
"I support her aims to reverse the national insurance increase and put a temporary halt on energy levies to help people with the cost of their energy. I believe, as does Liz, that the best way to help people in these challenging times is to let them keep more of their money and to encourage entrepreneurism and investment."
Ms Truss also has the backing of Wendy Morton, Sir Bill Cash, Marco Longhi, Michael Fabricant, Amanda Milling, Jane Stevenson and Shaun Bailey, as well as West Midlands Mayor Andy Street.
Ms Truss's opponent, former Chancellor Rishi Sunak, has been publicly backed by Sir Gavin Williamson, James Morris and Mike Wood.