The Honourable Company of Master Mariners is one of the Livery Companies of the City of London. The Company was formed in 1926; it was made a Livery Company by the City of London in 1932, making it the first new Livery Company to be formed in over a century. While the other Livery Companies are entitled to the style Worshipful, the Master Mariners are styled Honourable, King George V having granted them that honour in 1928.
The Company aids nautical schools and promotes nautical research. It ranks seventy-eighth in the order of precedence for Livery Companies. Its motto is Loyalty and Service.
The Honourable Company of Master Mariners has a headquarters ship, HQS Wellington, moored on the Thames at Victoria Embankment.