William Nugent Macnamara or M'Namara (c. 1776 – 11 November 1856) was an Irish landowner and Member of Parliament. He was the eldest son of Irish MP Francis Macnamara of Doolin and was educated at a Dublin seminary. He entered the local militia as a captain of grenadiers, later gaining promotion to major. He was appointed High Sheriff of Clare for 1798–99, successfully keeping order during the Irish rebellion, and succeeded his father in 1815 as landlord of Doolin. He later acquired Ennistymon House by marriage into the Finucane family.