István Abonyi (18 August 1886 – 5 June 1942) was a Hungarian chess master, who was born and died in Budapest.
István Abonyi with Zsigmond Barász and Gyula Breyer developed the Budapest Gambit.
Abonyi played it against the Dutch surgeon Johannes Esser in a small tournament at Budapest 1916.
He published analysis on the Abonyi Variation of the Budapest Gambit (1.d4 Nf6 2.c4 e5 3.dxe5 Ng4 4.e4 Nxe5 5.f4 Nec6) in 1922 in Deutsches Wochenschach.
[1] On January 21–22, 1928, Abonyi played 300 opponents on 105 boards in Budapest, scoring 79 wins, 6 losses, and 20 draws.