Hampson Hughes Solicitors has agreed a long-term lease on 34,512 sq ft of space at the historic Edward Pavilion building at Liverpool's Albert Dock.
The legal practice's 270-strong work force, currently located at the Cotton Exchange on Old Hall Street, will move into the top two floors of the grade 1-listed building.
Further expansion is planned by the no-win no-fee solicitor.
John Hughes, Hampson Hughes' joint managing director, said: "The Edward Pavilion is an iconic building with stunning views across the Albert Dock and Mersey waterfront.
"We chose it because it can accommodate our ambitious growth plans but also because it is steeped in history and we hope it will be our home for many years to come."