Gerard Slevin (born November 1, 1919) was born in Cork, Ireland. Slevin was assistant to Edward McLysaght, the Chief Herald of Ireland, from 1944 to 1954, at which time he succeeded McLysaght. He held this position for 27 years until he retired in 1981.

Slevin also designed the flag of the EU, a circle of 12 golden stars on a deep blue background, and in recognition of this was made a member of the Academie Internationale d'Heraldique.