Day, Summers and Company
| Industry | Engineering | 
|---|---|
| Founded | 1834 | 
| Founder | William Alltoft Summers, John Thomas Groves, Charles Arthur Day, William Baldock | 
| Headquarters | ,  England  | 
| Products | Locomotives and shipbuilding | 
Day, Summers and Company was a British steam locomotive manufacturer and shipbuilder in the Southampton area. The company's history is complex and involves five men: William Alltoft Summers, John Thomas Groves, Charles Arthur Day, William Baldock and Nathaniel Ogle.