| Ernst Fiedler | |
| Birth Date: | 22 July 1861 |
| Birth Place: | Chemnitz, Germany |
| Death Place: | Zürich, Switzerland |
| Resting Place: | Enzenbühl cemetery (Zürich) |
| Resting Place Coordinates: | 47.3495°N 8.5814°W |
| Spouse: | Lina Knoch |
| Parents: | Wilhelm Fiedler and Elise Springer |
| Field: | Mathematics |
| Work Institutions: | Kantonsschule Rämibühl |
| Alma Mater: | University of Leipzig ETH Zurich |
| Thesis Title: | Über eine besondere Klasse irrationaler Modulargleichungen der elliptischen Funktionen |
| Thesis Url: | https://books.google.com/books?id=ajULAAAAYAAJ |
| Thesis Year: | 1885 |
| Doctoral Advisor: | Felix Klein, Wilhelm Wundt |
Ernst Fiedler (22 July 1861 – 16 July 1954) was a German-born Swiss mathematician.
Fiedler was the son of Wilhelm Fiedler, mathematics professor at ETH Zurich from 1867. From 1879 to 1882 he studied mathematics at ETH Zurich; in 1882 he moved to Berlin where he studied under Weierstrass, Frobenius and other outstanding mathematicians. In 1885 he moved to Leipzig, where he was awarded a doctorate under Felix Klein in 1885.
Returned to Zürich, he was privatdozent at ETH Zurich. In 1889 he was named full professor at the Industrieschule (in 1904 renamed as Oberrealschule, and now Kantonsschule Rämibühl). He was the principal of the school from 1904 to 1926 when he retired.
Fiedler only produced some secondary school textbooks and any research paper. But he has left some lecture notes on courses given by his father and other professors like Weierstrass.
He also joined the Swiss Army and became the youngest colonel in the army. From 1889 he lectured on ballistics at the Polytechnicum. He was also member of a number of committees to improve the secondary schools.