Emma Mærsk is the first container ship in the E class of eight owned by A.P. Møller – Mærsk A/S. When launched in 2006, she was the largest container ship ever built, and in 2010, she and her seven sister ships were among the longest container ships. Officially, she is able to carry around 11,000 twenty-foot equivalent units (TEU) or 14,770 TEU, depending on definition. In May 2010, her sister ship Ebba Mærsk set a record of 15,011 TEU in Tanger-Med, Tangier.

A container ship is a cargo ship that carries all of its load in truck-size intermodal containers, in a technique called containerization. Container ships are a common means of commercial intermodal freight transport and now carry most seagoing non-bulk cargo.