Miles Henry 'Peter' Easterby (born 5 August 1929) is a British retired racehorse trainer.
From starting with seven horses at his stables at Habton Grange near Malton, North Yorkshire in 1950, he became one of the most successful trainers in British racing by the time he retired in February 1996.
In the late 1970s and early 1980s Peter Easterby's stable housed two of the leading horses in British National Hunt racing.
Sea Pigeon won the Champion Hurdle in 1980 and 1981 and was also the winner of the Ebor Handicap and Chester Cup (twice) in flat racing.
In July 2009, he was convicted of an offence under the Hunting Act 2004 after allowing his land to be used for a hare coursing event.