Blotter might refer to:
- Blotting paper, used to absorb ink or oil from writing materials, particularly when quill or fountain pens were popular
- Blotter (album), a 1996 album by the American band Nightstick
- Blotter, a means of transporting and taking lysergic acid diethylamide (commonly known as LSD or acid) and additional psychedelic compounds active in similarly low doses, by dipping it in blotting paper and allowing it to dry
- Police blotter, a daily record of arrests and additional events at a police station
- Blotter, the fourth track of the album Stone Sour by the band of that same name
- Blotter, the tool used to show a user's recent actions on the Steam (software) community page.
- Desk pad, a table protector used when work such as painting or writing would otherwise damage the table or desk