| Lord Frederick FitzRoy | |
| Office: | Member of Parliament for Thetford |
| Term Start: | 13 April 1864 |
| Term End: | 23 April 1866 |
| Alongside: | Alexander Baring |
| Predecessor: | William FitzRoy Alexander Baring |
| Successor: | Alexander Baring Robert Harvey |
| Birth Date: | 4 April 1823 |
| Nationality: | British |
| Party: | Liberal |
| Parents: | Henry FitzRoy Mary Caroline Berkeley |
| Relatives: | William FitzRoy (brother) Augustus FitzRoy (brother) |
| Children: | Five |
Lord Frederick John FitzRoy (4 April 1823 – 12 February 1919) was a British Liberal Party politician.
FitzRoy was the son of Henry FitzRoy and Mary Caroline FitzRoy (née Berkeley. In 1853, he married Catherine Sarah Wilhelimna Wescomb, daughter of William Wescomb, and they had five children, one son and four daughters.
FitzRoy was elected Liberal MP for Thetford at a by-election in 1863—caused by the succession of his brother William FitzRoy to 6th Duke of Grafton—and held the seat until 1865 when he stood down to seek election in South Northamptonshire, where he was unsuccessful.[1]
FitzRoy was also a Justice of the Peace for Sussex and Northamptonshire, and a Colonel in the Grenadier Guards.