A Tijuana Bible is a miniature comic with eight or (less commonly) sixteen single-panel pages, usually depicting notable figures such as cartoon characters, comic strip characters, or contemporary celebrities in sexual situations. They were often printed cheaply and sold in secret due to the sale of pornographic content being illegal at the time, as well as their frequently copyright-violating nature. Being at their height in the 1920s and 1930s, they're considered to be one of the earliest known instances of what's now known as "rule 34", before declining in the 1950s and 1960s.

Though millions were once in circulation, relatively few have survived to the modern day due their illegal nature leading to most having being seized and destroyed by law enforcement, as well as the increasingly poor quality of the prints as the format approached the end of its lifespan.