Guihomar III of Léon (died c. 1157) was a Viscount of Léon. He succeeded his father Harvey I.
Very few things are known about Guihomar III’s life.
His name appears firstly in the charter of foundation of the priory Saint-Martin of Morlaix made by his father in 1128.
He is also cited in the charter of the foundation of the priory of Saint-Melaine of Morlaix (c. 1145-1147) made by his son Harvey II, who mentions “pater meus G. vicecomes”.
The name of Guihomar’s wife is not known. They had two sons :