Sir Frederick Hamilton (1590–1647) was a Scottish nobleman and soldier.
Frederick Hamilton was the youngest son of Claud Hamilton, 1st Lord Paisley and his wife Margaret Seton, daughter to George Seton, 5th Lord Seton. He married Sidney Vaughan on May 20, 1620. She was the daughter of Sir John Vaughan, who was the Governor of Londonderry. Sir Frederick was given lands in Leitrim, in the northwest of Ireland in 1622.
Over the next two decades he increased his estate to 18,000 acres (73 km²) and built Manorhamilton Castle around which grew the town of Manorhamilton.
In November 1631, Sir Frederick entered Swedish service and became colonel of a Scottish-Irish regiment which served in Germany for 15 months. They fought General Tott's army in the Elbe and Weser basins and the Rhineland. After spending a few years back in Leitrim he unsuccessfully attempted to re-enter Swedish service in September 1637.
On the 5th December 1640, the Committee of Irish affairs of the Long Parliament supported a petition from a native nobleman, "Tirlagh Mac Raghnaill (Reynolds) of Kiltubrid" in Muintir Eolais, complaining "hee had been prosecuted uniustlie for lands in the Countie of Leytrim in Ireland" by "Sir Fredericke Hambledon".
During the Irish Rebellion of 1641, Manorhamilton came under constant siege, but the castle remained intact. After the 1643 Cessation he became a colonel of a regiment of horse in the army of the Solemn League and Covenant in fScotland and Northern England, while still retaining his foot regiment in western Ulster.