UK Box Office 15th December, 1978
| Title | Weekend | Week | Total | % Change | Total Weeks | ||
| 1 (new) |  | Superman (1978) | £1,001,289 | £1,001,289 | £1,001,289 | new | 1 |
| 2 (new) |  | Watership Down (1978) | £354,645 | £354,645 | £354,645 | new | 1 |
| 3 (1) | Piranha (1978) | £47,096 | £68,289 | £628,074 | -52% | 4 | |
| 4 (2) |  | Heaven Can Wait (1978) | £20,546 | £27,737 | £1,274,807 | -37% | 8 |
| 5 (3) | Force 10 From Navarone (1978) | £6,602 | £9,243 | £237,160 | -52% | 5 | |
| 6 (5) |  | The Cat From Outer Space (1978) | £3,584 | £4,838 | £809,192 | -47% | 8 |
| 7 (6) |  | Grease (1978) | £1,749 | £2,536 | £4,076,665 | -41% | 14 |