A spider hole is U.S. military parlance for a camouflaged one-man foxhole, used for observation. A spider hole is typically a shoulder-deep, protective, round hole, often covered by a camouflaged lid, in which a soldier can stand and fire a weapon. A spider hole differs from a foxhole in that a foxhole is usually deeper and designed to emphasize cover rather than concealment.

The term is usually understood to be an allusion to the camouflaged hole constructed by the trapdoor spider. According to United States Marine Corps historian Major Chuck Melson, the term originated in the American Civil War, when it meant a hastily-dug foxhole. Spider holes were used during World War II by Japanese forces in many Pacific battlefields, including Leyte in the Philippines and Iwo Jima. They called them "octopus pots" for a fancied resemblance to the pots used to cook cuttlefish in Japan.

Spider holes were also used by Vietnamese Communist fighters during the Vietnam War.

The American columnist William Safire claimed in the December 15, 2003, issue of the New York Times that the term originated in the Vietnam War. According to Safire, one of the characteristics of these holes was that they held a "clay pot large enough to hold a crouching man." If the pot broke, the soldier was exposed to attack from snakes or spiders, hence the name "spider hole".