Sir Edwin John Butler CMG CIE FRS[1] (13 August 1874 – 4 April 1943) was an Irish mycologist and plant pathologist.

He initially went to school in Gainsborough, Lincolnshire but returned to Ireland in 1887 due to illness and studied under a tutor.

A library in Cahersiveen where his father was transferred helped him develop an interest in a diverse range of topics.

In 1900, at the recommendation of the Royal Botanic Gardens, Kew, he was appointed as the first Cryptogamic Botanist to the Government of India at Calcutta.

[2][3] Between 1910 and 1912 Butler additionally held the office of Director and Principal at the Agricultural College in Pusa.

[1] In 1920, Butler returned to the United Kingdom to take up the post of director at the new Imperial Bureau of Mycology at Kew, Surrey, which was intended to research and provide information on plant diseases throughout the British empire.

[1] Butler subsequently became the first paid secretary of the Agricultural Research Council until ill-health forced his retirement in 1941.