The firm, founded by business lawyer and mediator Rashmi Dubé, now occupies a 1046 sq ft office at Kings House on King Street, double the size of its previous office.
Legatus is made up of a team of business lawyers for SMEs and specialises in shareholder disputes, management buyouts and technology.
Dubé said: “It’s a very exciting time for Legatus as we continue to grow and cement our foundations in Leeds.
“After two years in business we needed to move to new premises to allow for our continued expansion and by doubling the size of office space we are able to do that.
“We have plans in place to further expand our team over the next few months which will allow us to provide bespoke, expert advice to businesses.
“We’re now looking forward to welcoming them to our brand new headquarters and working with them in 2016.”
Since launching in 2013, Legatus has also opened a base in the City of London.