| One Man and His Dog | BBC Two | — | — | — |
| One Man and His Hob | — | — | — | 13 |
| One Night | BBC One | — | 1 | 4 |
| One Pair of Eyes | — | — | — | — |
| One Summer | — | — | — | 5 |
| Only an Excuse? | BBC One | sitcom | — | 20 |
| Only Child | — | — | — | — |
| Only Fools and Horses | BBC One | sitcom | 7 | 64 |
| Only Human | Channel 4 | documentary film, documentary television program | — | — |
| Only When I Laugh | ITV | sitcom | 4 | 29 |
| OOglies | — | comedy television series | 3 | 46 |
| Ooh La La! | — | — | — | — |
| Oops TV | — | — | 2 | 107 |
| Open Air | BBC One | — | 4 | — |
| Open All Hours | BBC Two | sitcom | 4 | 26 |
| Open House | — | — | — | — |
| Open House with Gloria Hunniford | Channel 5 | — | 6 | 135 |
| Open to Question | BBC Scotland | current affairs | — | — |
| Opening Shot | — | — | — | — |
| Operation Good Guys | BBC Two | comedy television series | 3 | 19 |
| Operation Grand Canyon with Dan Snow | BBC Two | — | 1 | 2 |
| Operation Ouch! | BBC Children's and Education | — | 6 | 55 |
| Opinions | — | — | — | — |
| Orange Playlist | — | — | — | — |
| Orange unsignedAct | Channel 4 | — | — | — |
| Oranges Are Not the Only Fruit | BBC Two | LGBT-related television series | — | 3 |
| Orangutan Diary | — | nature documentary | — | 11 |
| Orangutan Jungle School | — | — | 3 | — |
| Orchestra United | — | — | — | — |
| Ordeal by Innocence | BBC One | thriller television series, drama television series | — | 3 |
| Order to View | — | — | — | — |
| Ordinary Lies | — | — | 2 | 6 |
| Origins of Us | — | documentary film | — | — |
| Orlando | ITV | thriller television series | 4 | 76 |
| Orm and Cheep | ITV | children's television series | — | 26 |
| Orson Welles' Great Mysteries | ITV | anthology series | 1 | 26 |
| Orson Welles' Sketch Book | — | — | 1 | 6 |
| Oscar | — | — | 1 | 3 |
| Oscar Charlie | — | children's television series | — | — |
| Other People's Children | BBC One | drama television series | 1 | 4 |
| Our Crime | — | documentary film | — | — |
| Our Friends in the North | BBC Two | drama television series | — | 9 |
| Our Girl | BBC One | drama television series | 4 | 28 |
| Our House | ITV1 | sitcom | 2 | 39 |
| Our Man in... | Channel 4 | documentary television program | 1 | 3 |
| Our Miss Pemberton | — | — | — | — |
| Our Mutual Friend | BBC Two | — | — | 4 |
| Our Mutual Friend | BBC One | — | 1 | 12 |
| Our Mutual Friend | British Broadcasting Corporation | — | 1 | 7 |
| Our Oceans | — | — | — | — |
| Our Planet | Netflix | documentary film | 2 | 12 |
| Our School | — | — | — | — |
| Our World War | BBC Three | docudrama | 1 | 3 |
| Our Zoo | BBC One | drama | 1 | 6 |
| Out Of Bounds | BBC One | drama television series | 1 | 6 |
| Out of Her Mind | BBC Two | — | — | — |
| Out of Sight | ITV | comedy television series, children's television series | 3 | 27 |
| Out of Step | — | — | — | — |
| Out of the Blue | — | crime television series | 2 | 12 |
| Out of the Unknown | BBC Two | science fiction television series, fantasy television series, anthology series | 4 | 49 |