| Honorific Prefix: | The Right Honourable |
| The Earl of Munster | |
| More: | no |
| Spouse: | Wilhelmina Kennedy-Erskine |
| Issue: | Edward, Viscount FitzClarence Hon. Lionel Frederick Archibald Geoffrey FitzClarence, 3rd Earl of Munster Hon. Arthur Falkland Manners Aubrey FitzClarence, 4th Earl of Munster Hon. William George Hon. Harold Edward Lady Lillian Boyd Lady Dorothea Lee-Warner |
| Noble Family: | FitzClarence |
| Father: | George FitzClarence, 1st Earl of Munster |
| Mother: | Mary Wyndham |
| Birth Date: | 19 May 1824 |
| Birth Place: | Dun House, Montrose, Scotland |
William FitzClarence, 2nd Earl of Munster, (19 May 1824 – 30 April 1901), styled Viscount FitzClarence from 1831 to 1842, was a British peer. He was named after his grandfather, King William IV.
FitzClarence's father, George FitzClarence, 1st Earl of Munster, was an illegitimate son of King William IV by his long-time mistress Dorothea Jordan. Therefore, the second Earl of Munster was the great-grandson of King George III and first cousin once removed of Queen Victoria. His mother was Mary Wyndham (d. 3 December 1842), the illegitimate daughter of George Wyndham, 3rd Earl of Egremont.
FitzClarence succeeded as the 2nd Earl of Munster on the suicide of his father, on 20 March 1842. For the most part, FitzClarence led a typical Victorian upper-class life of hunting parties and balls.
He purchased a commission as ensign and lieutenant in the Scots Fusilier Guards on 1 July 1842. On 7 April 1843, he purchased a cornetcy and sub-lieutenancy in the Grenadier Guards. He purchased a lieutenancy on 1 May 1846 and a captaincy on 16 March 1849. Munster retired from the Army in April 1851.
FitzClarence married his first cousin Wilhelmina Kennedy-Erskine (27 June 1830 – 9 October 1906) on 17 April 1855. Her mother, Augusta FitzClarence, was the sister of his father, George Augustus FitzClarence. In later life, she became a novelist. They had nine children:
Lord Munster died in 1901, at 23 Palmeira Square, Hove, at the age of 77, when his second cousin Edward VII was on the throne of the United Kingdom. He was buried at Cuckfield, Sussex. He was succeeded in the earldom and other titles by his third eldest son, Geoffrey.