1786 in sports

1786 in sports describes the year's events in world sport.

Boxing
Events
 * 11 January — Tom Johnson defeated Bill Lowe at Barnet in the first round after four minutes.
 * 11 February — Tom Johnson defeated Jack Towers at Barnet in a 15-minute fight.
 * 31 October — "Big" Ben Brain defeated "The Fighting Grenadier" John Boone at Long Fields in a 30 to 40 minute fight, depending on the source.

Cricket
Events England
 * Tom Sueter of Hampshire was given out for hitting the ball twice, the first recorded instance of this type of dismissal.
 * First-class debut of the noted opening batsman Tom Walker, who is believed to have invented roundarm bowling.
 * Most runs – Tom Walker 423
 * Most wickets – Robert Clifford 23

Horse racing
England
 * The Derby – Noble
 * The Oaks – Yellow Filly
 * St Leger Stakes – Paragon
 * The inaugural July Stakes was run at Newmarket Racecourse and is the oldest race for two-year-olds still run in Great Britain.