East Mayo was a parliamentary constituency in Ireland, which returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom from 1885 to 1922.

Prior to the 1885 general election the area was part of the Mayo constituency. From 1922, on the establishment of the Irish Free State, it was not represented in the UK Parliament.

This constituency comprised the eastern part of County Mayo.

1885–1922: That part of the barony of Costello not contained within the constituency of South Mayo and that part of the barony of Gallen not contained within the constituency of North Mayo.

• Walker, Brian M., ed. (1978). Parliamentary Election Results in Ireland, 1801–1922. Dublin: Royal Irish Academy. pp. 366–367, 394. ISBN 0901714127.
• Leigh Rayment's Historical List of MPs – Constituencies beginning with "M" (part 2)