The agency wrestled the business from incumbent Weber Shandwick following a six-way shoot-out that also involved FD, Citigate Dewe Rogerson, Kinross + Render and Mainstream.
The three-year contract is believed to be worth in excess of £250,000 a year in fees.
The Isle of Man’s tourism-related PR will continue to be led by Weber Shandwick. Lanson’s brief is to handle all of the island’s non-tourism related PR.
The agency will be charged with enhancing the island’s economic reputation and raising its profile throughout the world.
The financial services sector is seen as a key area of growth for the Isle of Man, and the programme will also see the agency encouraging inward investment and promoting the island’s manufacturing industries.
Much of the work will be concentrated on the UK, but it will also include a focus on such diverse parts of the world as Washington and Asia. Part of the brief is to differentiate the Isle of Man positively from other European financial centres, such as Jersey.
Lansons is part of Public Relations Organisation International, the global network of independent PR agencies, and will work with those partners in key locations.
The account will be led by chief executive Tony Langham. Head of public affairs Ben Abbotts, head of Lansons Live Christian Mahne, and associate director Lyndsay Haywood are also on the team.
The Isle of Man government received pitches from almost 30 agencies during a review process that began back in April.