A V16 is an internal combustion engine in V configuration, having 16 cylinders. Engines of this number of cylinders are not common.

V16 engines have been used in certain luxury and high-performance automobiles, mostly for their smoothness characteristics since one can certainly make a V8 or V12 as large as one could possibly want for automotive purposes. Certain Cadillacss in the late 1920s and early 1930s were fitted with V16 powerplants, as were the revived Bugattis of the 1990s.

The other use for the V16 powerplant is in large diesel engines. Here, the manufacturers tend to work with a common cylinder size across a wide range of engines, and size the engine by the number of cylinders for different power requirements. Thus, many users of large diesel engines such as railroad locomotives use V16 powerplants, including many General Motors Electro-Motive Division locomotives.