| Ernst Wagner | |
| Birth Date: | 14 August 1876 |
| Birth Place: | Hildburghausen, German Empire |
| Death Place: | Würzburg, Germany |
| Nationality: | German |
| Fields: | Physicist |
| Workplaces: | University of Würzburg University of Munich |
| Alma Mater: | University of Würzburg University of Berlin University of Munich |
| Doctoral Students: | Helmuth Kulenkampff |
Ernst Wagner (1876–1928) was a German physicist. He was born on 14 August 1876 at Hildburghausen. He first studied medicine and physics at the Universities of Würzburg, Berlin, and Munich, obtaining his doctorate under Wilhelm Röntgen in 1903. He became Privatdozent in spring 1909 and extraordinary professor in 1915 at the University of Munich. Wagner was notable for his work on X-rays and on the absolute measurement of high pressure.