Blotter may 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) by dipping it in blotting paper and allowing it to dry
- Police blotter, a daily record of arrests and other 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 users recent actions on the Steam_(software) community page.