Harold Segerson Mahony (13 February 1867 – 27 June 1905) was a Scottish-born Irish tennis player who is best known for winning the singles title at the Wimbledon Championships in 1896.

[3] Mahony spent some time in America in the mid-1890s, before returning to the United Kingdom and finally taking the Wimbledon crown in 1896.

[9] Mahony was a member of the 1903 British Isles Davis Cup team that won the against the United States at the Longwood Cricket Club in Boston but did not play in the event.

When four-time Wimbledon champion Reginald Doherty had a shoulder injury the British team captain William Collins elected to forfeit his first match, instead of letting Mahony play, so that Doherty would be allowed to play the reverse singles match later in the event.

[3] Mahony was killed on 27 June 1905, aged 38, in a bicycling accident while descending a steep hill near Caragh Lake in County Kerry.