The agency's endorsement comes a week after the campaign received the vocal support of prime minister David Cameron and culture secretary Jeremy Hunt.
Jane Baker, CWT Meetings & Events' business development manager, said: "Our support is a reflection of the growth and importance of the meetings and events sector.
"We work with some of the most successful and innovative companies in Britain who use meetings and events to motivate, educate and connect with their customers, partners and people. Live experiences provide organisations with a powerful and measurable marketing tool."
Michael Hirst, the campaign coordinator and chairman of Business Visits & Events Partnership, added: "Having the support of CWT Meetings & Events represents another great endorsement for the campaign which now covers the full spectrum of organisations from buyers and suppliers to stakeholder and government organisations.
"CWT Meetings & Events adds a credible and recognised voice to the campaign from a professional and successful event organising business. We're delighted to have them on board."