Dénes Kőnig (September 21, 1884 – October 19, 1944) was a Jewish Hungarian mathematician who worked in and wrote the first textbook on the field of graph theory.

Kőnig was born in Budapest, the son of mathematician Gyula Kőnig. In 1907, he received his doctorate at, and joined the faculty of the Technische Hochschule in Budapest (today Technical University of Budapest). His classes were visited by Paul Erdős, who, as a first year student, solved one of his problems. Kőnig became a full professor there in 1935.

In the days of the 1944 antisemitic atrocities in Budapest, he committed suicide.