Applicants who have joined the scheme launched in October 2007 include the Ritz, the O2 Centre and the Royal Lancaster Hotel and they will now receive advice on how to green up their act.
Advisors will then assess the progress the companies are making in areas including energy reduction and waste disposal before giving them either bronze, silver or gold awards.
LDA chief executive Manny Lewis said: “All of London’s businesses have a responsibility to help prevent runaway climate change.
“In signing up to the Green Tourism for London scheme these hotels and attractions are not just doing their bit for the environment but are making huge savings in their energy and water costs.
“I would encourage all hotels across the capital to get assessed, earn their awards and help ensure London continues to lead the way in tackling global warming.”
Visit London chief executive James Bidwell added: “Climate change is perhaps the most critical issue facing the planet today and all industries have a part to play, in particular the tourism industry.”