A bug zapper, or more formally an electrical discharge insect control system is a device that attracts and kills flying insects that are attracted by light. A light source attracts insects to an electrical grid, where they are electrocuted by touching two wires with a high voltage between them. The name stems from the characteristic zap sound produced when an insect is electrocuted.

In its October 1911 issue, Popular Mechanics magazine had a piece showing a model "fly trap" that used all the elements of a modern bug zapper, including electric light and electrified grid. The design was executed by two unnamed Denver men and was conceded to be too expensive to be of practical use. The device was 10 by 15 inches (25 by 38 cm), contained 5 incandescent light bulbs, and the grid was ¹⁄₁₆-inch (1.59 mm) wires spaced ¹⁄₈-inch (3.18 mm) apart with a voltage of 450 volts. Users were supposed to bait the interior with meat.

According to the US Patent and Trademark Office, the first bug zapper was patented in 1934 by William F. Folmer and Harrison L. Chapin. They were issued U.S. Patent 1,962,439.