The landing craft mechanized (LCM) is a military landing craft designed for carrying personnel and vehicles from ship to shore without requiring a pier or other shore-based structure. Multiple different models with varying size, capacity, and power plants were produced starting in 1920. They came to prominence during the Second World War when they were used to land troops and tanks during Allied amphibious assaults.

There was no single design of LCM used, unlike the landing craft, vehicle, personnel (LCVP) or landing craft assault (LCA) landing craft made by the US and UK respectively. There were several different designs built by the UK and US and by different manufacturers.

The British motor landing craft (MLC) was conceived and tested in the 1920s and was used from 1924 in exercises. Nine were in service at the start of the war. It was the first purpose-built tank landing craft. It was the progenitor of all subsequent LCM designs.

The landing craft, mechanised Mark I, was an early British model. It was able to be slung under the davits of a liner or on a cargo ship boom with the result that it was limited to a 16-ton tank.^{[clarification needed]}

The LCM Mark I was used during the Allied landings in Norway (one alongside the MLCs), and at Dieppe and some 600 were built.

The first American LCM design, from the US Navy's Bureau of Construction and Repair. Approximately 150 were built by American Car & Foundry and Higgins Industries.

There were two designs:

Capable of carrying 120,000 lb (54,000 kg) of cargo