Workers are 3/8 to 5/8 inch long, and queens are up to 7/8 to 1 inch long. Black and yellow stripes are the most common colors of various pest species. Yellowjacket bodies are hairless or have only a few hairs, and the front of the abdomen is blunt, not rounded; the legs are short compared to those of the European paper wasp. Yellowjacket flight behavior is distinct, as they tend to fly sideways, left to right, as they zone in on something.

Yellowjackets are social wasps that live in annual colonies of one queen and 1,000 to 5,000 workers. In the southeastern United States colonies can persist year to year and grow much larger than in the Northeast. Inseminated queens overwinter and initiate colonies in springtime by choosing a suitable cavity or location and constructing the first comb of cellulose (chewed wood and paper particles). The queen lays and cares for the first eggs, and when these adult females emerge, they take over colony maintenance, enlargement, defense, foraging, and brood care, while the queen devotes herself to laying eggs. German, common, and eastern yellowjackets are commonly void-nesters and will use mouse burrows and natural cavities, as well as structural voids. Aerial yellowjackets will build nests in shrubs, trees, and on the sides of buildings. The nest consists of several tiers of comb wrapped in a delicate gray paper envelope and is usually round but may take on the shape of the space chosen for nesting. Yellowjackets are predators of other insects and considered beneficial. However, several species, including the German, eastern, and common yellowjackets, are scavengers that will forage around carcasses, trash, and human activities involving food.

Yellowjackets are commonly found in and around structures in both urban and rural areas. When yellowjackets colonize or forage around areas of human activity, they become a nuisance and also a significant threat to certain people. Their stings are painful and can result in serious illness or death for some allergic individuals. When yellowjacket nests are built inside wall voids of structures, yellowjackets often find their way inside occupied indoor spaces, which can be extremely disruptive or dangerous. Colonies in structures can attract carpet or hive beetles after the colony has died off in late autumn. If entry points are not closed up, the space may be used repeatedly year after year.