Back door may refer to:
- Backdoor (computing), is a hidden method for bypassing normal computer authentication systems.
- Back Door (jazz trio), a British jazz trio, drums sax and bass guitar, who played in the bar of the highest pub on the Yorkshire moors during the late 1970s. Their use of the bass guitar was ahead of its time.
- The Back Door (fiction), an 1897 work describing a fictional French and Russian invasion of Hong Kong
- The Back Door (album), a 1992 album by American band Cherish the Ladies
- Backdoor pilot, is a method used to judge reaction to a potential new television series.
- In Jazz Music Theory, a Backdoor Progression is a characteristic harmonic device found in many Jazz Standards.