Ruston & Hornsby
| Ruston & Hornsby logo | |
| Company type | Private | 
|---|---|
| Industry | Engineering | 
| Predecessor | Ruston, Proctor and Company | 
| Founded | 1918 | 
| Fate | Purchased by English Electric | 
| Headquarters | Waterside South, Lincoln, England | 
| Products | Diesel engines, Locomotives, Steam engines, Gas turbines | 
| Parent | English Electric (1966–1968) GEC (1968–2003) Siemens (2003–) | 
| Subsidiaries | Ruston-Bucyrus | 
Ruston & Hornsby was an industrial equipment manufacturer in Lincoln, England founded in 1918. The company is best known as a manufacturer of narrow and standard gauge diesel locomotives and also of steam shovels. Other products included cars, steam locomotives and a range of internal combustion engines, and later gas turbines. It is now a subsidiary of Siemens, its Diesel business went to MAN Energy Solutions that in 2025 still provides support for Ruston-engines.