起重机船（英语：crane vessel、crane ship、floating crane），是一种各种重物悬吊的工作船。常用于海上的各种工程，或是悬吊起沉船。

A crane vessel, crane ship or floating crane is a ship with a crane specialized in lifting heavy loads. The largest crane vessels are used for offshore construction. Conventional monohulls are used, but the largest crane vessels are often catamaran or semi-submersible types as they have increased stability. On a sheerleg crane, the crane is fixed and cannot rotate, and the vessel therefore is manoeuvered to place loads.