Captain William Henry O'Shea was an Irish soldier and Member of Parliament. He is best known for being the ex-husband of Katharine O'Shea, the long-time mistress of the Irish nationalist leader Charles Stewart Parnell.

Katharine Parnell, known before her second marriage as Katharine O'Shea, and usually called Katie O'Shea by friends and Kitty O'Shea by enemies, was an English woman of aristocratic background whose decade-long secret affair with Charles Stewart Parnell led to a widely publicized divorce in 1890 and his political downfall.