A nymph is an immature, hemimetabolous insect. In insects that undergo a gradual metamorphosis, the stage of the life cycle that hatches from the egg is called the nymph. These insects do not pupate. Often, the nymph looks like a smaller, wingless version of the adult. The nymph may molt several times to reach adulthood.

Insects that undergo simple or gradual metamorphosis, and thus have a nymph stage, include grasshoppers and crickets, mantids, cockroaches, termites, dragonflies and damselflies, and all true bugs.