| Honorific-Prefix: | The Right Honorable |
| Ismania Catherine FitzRoy, Baroness Southampton | |
| Spouse: | Charles FitzRoy, 3rd Baron Southampton |
| Children: | Hon. Ismay Mary Helen Augusta FitzRoy Frederica Louise Fitzroy Hon. Blanche Georgiana Fitzroy Charles Henry Fitzroy, 4th Baron Southampton Captain Rt. Hon. Edward Algernon FitzRoy |
| Parents: | Walter Nugent, 1st Baron Nugent Georgiana Elizabeth Jenkinson |
| Birth Name: | Ismania Catherine Nugent |
| Birth Date: | 1838 9, df=yes |
| Birth Place: | Ireland |
| Death Place: | Park Place, Englefield Green |
Ismania Catherine FitzRoy, Baroness Southampton (née Nugent; 23 September 1838 – 18 August 1918) was an Irish aristocrat, the wife of Charles FitzRoy, 3rd Baron Southampton. She served as Lady of the Bedchamber to Queen Victoria.
Ismania Catherine Nugent was born on 23 September 1838[1] in County Westmeath in Ireland.[2] [3] Her father was a Baron of the Austrian Empire, Walter Nugent, 1st Baron Nugent, while her mother was his second wife, Georgiana Elizabeth Jenkinson.
On 25 February 1862 she married Charles FitzRoy, 3rd Baron Southampton, becoming his second wife. He had no children by his first wife. They had five children.[4]
He died after just ten years of marriage and as a result FitzRoy remained the Dowager Baroness for another 45 years.
In 1878, some years after the death of her husband, she was appointed Lady of the Bedchamber to Queen Victoria and served in that capacity until 1901. For her service to the Queen she was awarded The Royal Order of Victoria and Albert. However she did not make an entirely good impression on another lady-in-waiting Marie Mallett who wrote in her diary in 1888 that ‘Lady Southampton is most kind but her dullness is beyond description".[5]