| Option Lock | |
| Author: | Justin Richards |
| Series: | Doctor Who book: Eighth Doctor Adventures |
| Release Number: | 8 |
| Subject: | Featuring: Eighth Doctor Sam |
| Release Date: | February 1998 |
| Publisher: | BBC Books |
| Isbn: | 0-563-40583-X |
| Preceded By: | Kursaal |
| Followed By: | Longest Day |
Option Lock is an original novel written by Justin Richards and based on the long-running British science fiction television series Doctor Who. It features the Eighth Doctor and Sam.
The Doctor and Sam land in present-day England on the ancestral home of the Silver family. However, the house holds clues to a dangerous centuries-old society and something that drove a man to suicide. Unravelling this will take Sam and the Doctor through time and space to save Earth from nuclear fire.