| S. L. Loney | |
| Birth Date: | 16 March 1860 |
| Birth Place: | Chevithorne, Devon, England |
| Death Place: | Richmond, London |
| Alma Mater: | Sidney Sussex College, Cambridge |
| Occupation: | Professor, author |
| Organization: | Royal Holloway College |
Sydney Luxton Loney, M.A. (16 March 1860 – 16 May 1939) was a Professor of Mathematics at the Royal Holloway College, Egham, Surrey, and a fellow of Sidney Sussex College, Cambridge, England. He authored a number of mathematics texts, some of which have been reprinted numerous times. He is known as an early influence on Srinivasa Ramanujan.[1]
Loney was educated at Maidstone Grammar School, in Tonbridge and at Sidney Sussex College, Cambridge, where he graduated with a B.A. as 3rd Wrangler in 1882. His books on Plane Trigonometry and Coordinate Geometry are very popular among senior high school students in India who are preparing for engineering entrance exams like JEE Advanced.[2]