The banana spider is a common name used for two entirely different species of spiders, the nephila clavipes of North America, and the phoneutria of Central and South America, the latter of which can be deadly.

The phoneutria or South American banana spider is a large, aggressive spider with a body length of about 1.3 inches (3 cm). This banana spider primarily makes its home in the rain forests but can also be found in cities, where, between 1970 and 1980 it was reportedly responsible for the hospitalization of some 7,000 people in southeastern Brazil.

The South American banana spider's venom is neurotoxic, or acts on the nervous system, and is similar to the venom produced by redback spiders, also known as black widows. A phoneutria banana spider's bite will cause immediate pain, a cold sweat and irregular heartbeat. Antivenin does exist and the bite can be deadly so immediate medical attention is necessary.

Other names for the dangerous phoneutria banana spider include: bananenspinne, kammspinne, and wandering spider.

The nephila clavipes banana spider of North America possesses venom similar in nature to the venom of the black widow, but far less potent, making it quite harmless to humans. A bite from a North American banana spider will not result in much more than a welt that will pass within 24 hours.

N. clavipes banana spiders have elongated bodies that resemble a banana in shape and coloring, beautifully bright yellow and black. The males are about half the size of females, and dark colored. Females grow quite large with a body length of about 1.1 inches (33 cm). North American banana spiders prefer sunny areas and tend to like tall plants or trees. They will often spin a web across a walkway or trail, spanning several feet. The web of the North American banana spider is orb-shaped, golden, and is stronger than most spiders' webs. In fact its silk is stronger than comparable threads of Kevlar® or steel.

The North American banana spider is not aggressive, but if you notice banana spiders building webs close to your home and would like them to move, simply tear down the webs. The spiders will relocate further away where they can continue to do their part in keeping down the insect population.

Other names for the N. clavipes or North American banana spider include the writing spider and golden orb weaver. The argiope or yellow and black garden spider is similar in size and sometimes confused with the banana spider. It too is known as 'the writing spider' due to zig-zag patterns in its web.

Although the bite from an N. clavipes banana spider is harmless, an allergic reaction could be severe. If you've been bitten by a spider of any kind and feel concerned, collect the spider, if possible, and see your doctor or contact your local poison center.