William O'Shea

Captain William Henry O'Shea (1840–22 April 1905) was an Irish soldier and Member of Parliament.

Born in Dublin, O'Shea was a captain in the 18th Hussars of the British Army.

Around 1880, his wife, Katharine O'Shea, entered into a relationship with Charles Stewart Parnell, with whom she had three children. O'Shea, who was already separated from his wife, knew of the affair. He only filed for divorce in 1890 after her aunt, from whom he was expecting a large inheritance, died in 1889 leaving her estate in trust for his wife (thus allegedly violating the terms of O'Shea's marriage contract). However, that will was overturned upon appeal, and the aunt's legacy was shared among Katherine O'Shea's siblings.

O'Shea was MP for Clare from 1880 to 1885 and Galway Borough for a short period in 1886. Although supported by Parnell, he was never a member of the Irish Parliamentary Party.