| Name | Book/story/stage title | Notes |
| Ickenham, Lord | 5th Earl of Ickenham, better known as Uncle Fred | |
| Inge | Blenkinsop's Benefit | Boy at Beckford College |
| Innes, James | A Benefit Match | A cricketer |
| Ippleton, Earl of | Bingo Bans the Bomb | Father of Mabel Murgatroyd |
| Isabel | Unpleasantness at Kosy Kot | Aunt of Clarissa Boote |
| Ivy | Do Butlers Burgle Banks? | Parlourmaid at Mallow Hall |