The Oasis class is a class of 7 Royal Caribbean International cruise ships. The first two ships in the class, Oasis of the Seas and Allure of the Seas, were delivered respectively in 2009 and 2010 by STX Europe Turku Shipyard, Finland. A third Oasis-class vessel, Harmony of the Seas, was delivered in 2016 built by STX France. A fourth vessel, Symphony of the Seas, was completed in March 2018. As of March 2022, the fifth Oasis-class ship, Wonder of the Seas, was the largest cruise ship in the world. A sixth ship, Utopia of the Seas, is currently being built for entry into service in July 2024 with a seventh to follow in 2028.

Royal Caribbean International (RCI), previously known as Royal Caribbean Cruise Line (RCCL), is a cruise line brand founded in 1968 in Norway and organized as a wholly owned subsidiary of Royal Caribbean Group since 1997. Based in Miami, Florida, it is the largest cruise line by revenue and second largest by passengers counts. In 2018, Royal Caribbean International controlled 19.2% of the worldwide cruise market by passengers and 14.0% by revenue. As of January 2024, the line operates 28 ships and has three additional ships on order.