Earwigs make up the insect order Dermaptera, found throughout the Americas, Eurasia and Australia. It is one of the smaller insect orders, with only 1,800 recorded species in 12 families. Typical earwigs have characteristic cerci, a pair of forceps-like pincers on their abdomen, and membranous wings folded underneath short forewings, hence the scientific name for the order, which translates literally as “skin wings”. Some groups within the earwig order are tiny parasites on mammals and lack the typical pincers. Earwigs rarely fly, even though they are capable of flight.

Earwigs are nocturnal; they often hide in small, moist crevices during the day, and are active at night, feeding on a wide variety of insects and plants. Damage to foliage, flowers, and various crops are commonly blamed on earwigs, especially the common earwig Forficula auricularia. However, the harmfulness of earwigs to foliage is still under debate, as they also eat certain insects that damage them.

Earwigs undergo an average of 5 molts over the course of a year, their average life expectancy, before they become adults. Many earwig species display maternal care, which is uncommon among insects. Female earwigs are known to take care of their eggs, and even after they have hatched as nymphs will continue to watch over offspring until their second molt. As the nymphs molt, sexual dimorphism such as differences in pincer shapes begins to show.

Earwig fossils have been found dating back 208 million years. Those specimens are now included in the extinct suborder Archidermaptera dating back to the Late Triassic. Many orders of insect have been theorized to be closely related to earwigs by many authors, though Grylloblattaria is the most likely.