The agency will handle an integrated communications strategy, including brand campaigns, new building launches, and press office.
Tin Man will also act as a strategic communications hub for Germany ahead of TOG's launch in Berlin, Frankfurt and Hamburg later this year.
Mandy Sharp, founder and chief executive of Tin Man, said: “We came up with a strategy that will create standout, relevancy and longevity, showing how The Office Group is using distinctive design and a people-first approach to make life better for its member businesses, people and wider culture."
Founded in 2003, TOG has more than 21,000 members in 39 workspace buildings in London, Leeds and Bristol.
“We need a communications strategy that will bring our brand purpose to life by creating an ownable market position which creates a real connection with our audience,” said Lorna Perrin, chief marketing officer at TOG.