The Wright Vertical 4 was an American aircraft engine built by the Wright brothers in the very early years of powered flight. It was a liquid-cooled piston engine with four inline cylinders, mounted vertically. It generated about 30–40 horsepower (22–30 kW) from a displacement of 240 cubic inches and weighed about 160–180 pounds (73–82 kg). Developed by Orville Wright in 1906, the Vertical 4 was produced by the Wright Company until 1912 and was the most numerous engine they manufactured. Around a hundred Vertical 4 engines were built, according to a Wright test foreman.

The Wright Company was the commercial aviation business venture of the Wright Brothers, established by them on November 22, 1909, in conjunction with several prominent industrialists from New York and Detroit with the intention of capitalizing on their invention of the practical airplane. The company maintained its headquarters office in New York City and built its factory in Dayton, Ohio.