Heathrow has become the latest travel supplier to join the GTMC.
The UK’s hub airport wants to use its membership of the organisation to raise its profile within the business travel industry.
Nigel Milton, Heathrow’s director of policy and political relations, said: “We work with a broad number of TMCs and see a huge volume of business travellers pass through the airport on a daily basis.
“Working with the GTMC and its network, we look forward to continuing to develop our offer and build for future expansion.”
Heathrow faces a crucial next year as it continues to move airlines into the new Terminal 2 and also lobbies to be allowed to build a third runway.
GTMC chief executive Paul Wait said: “The decision by Heathrow airport to join the GTMC is testament to the value it places on business travel and TMCs.
“Our recent air survey demonstrated that Heathrow continues to be a key airport for business travellers in the UK.
“The GTMC has been a long standing supporter of the campaign for increased capacity and the expansion of routes into business centres both here in the UK and globally. We look forward to working with the team at Heathrow to continue to drive this.”