MÁVAG (Magyar Királyi Államvasutak Gépgyára; Hungarian Royal State Railroads' Machine Factory) was a Hungarian rail vehicle producer. MÁVAG was the property of the Kingdom of Hungary. After the World War II MÁVAG was nationalized, and "Királyi" ("Royal") was removed from its name.
The company employed thousands of workers. The buildings were in the VIII. district of Budapest, bordered by the following streets: Kőbányai street, Hungária avenue, Vajda Péter street, and Orczy street. It was the most important Hungarian machine factory in the 19th century, along with Csepel Művek (Csepel Factories). The most respected products of MÁVAG were steam locomotives. The first was produced in 1873, and MÁVAG produced the famous locomotive no. 424 from 1924. MÁVAG's neighbouring company was the Ganz motor- és vagongyár (Ganz engine and wagon factory), which manufactured diesel locomotives and luxury carriages for export.
Up until 1959 the company produced 7578 locomotives. In 1896, when Hungary celebrated the 1000th anniversary of Hungarian settlement, the 1000th locomotive was exhibited. MÁVAG exported many locomotives: from 1900, to Italy and Romania, later to Egypt, India, Yugoslavia, and Korea. After 1945 the company exported diesel trains to the USSR, and in 1961 became well-known there for Д1 local diesel trains.
In 1959 MÁVAG merged with the Ganz company and was renamed Ganz-MÁVAG.