The recognition comes for his services to the maritime sector and his "pivotal role" in the resumption of cruising during the Covid-19 pandemic.
In response the award, Harmer said he "felt privileged" to work for an industry which employs people from all over the world.
"I’m thrilled and very grateful to receive this recognition," he added. "It has been an incredibly challenging few years for everyone in our sector and the way we have all worked together to overcome such enormous challenges has been inspiring.
"I feel privileged every day to work for an industry that employs people from all over the world, people of all backgrounds who are passionate about what they do, creating unforgettable travel experiences."
Meanwhile, Kelly Craighead, president and chief executive of Clia, said: "We send our warmest congratulations to our colleague Andy Harmer on receiving an OBE for services to the maritime sector.
"During the pandemic, Andy’s tireless commitment, combined with his collaborative and positive approach, set a fantastic example, and showed our industry at its best."
Harmer has worked in the travel industry for more than 24 years, including several years as a travel agent.