The accolade follows a Silver Status award handed to the agency at the 2009 ceremony.
Seventeen Events managing director Andrew Williams said the achievement was recognition of the agency's efforts to push the sustainability agenda.
"Being shortlisted in the Mayor of London's Green Procurement Code Awards is a huge honour for us," he said. "The fact that for the first time, Mayor Boris Johnson presented the awards is recognition of the increasing importance of sustainable procurement in London. With the Olympics fast approaching, I think that this is here to stay."