Leafhopper adults are elongated, wedge shaped and somewhat triangular. They jump and fly off readily, hence their name. Depending on species, they range in size from 1/8 to 1/2-inch and their bodies can come in many different colors, most commonly yellow, green, or in patterns.

Most species overwinter as eggs or adults. Eggs are inserted into leaf veins, shoots or stems of host plants. Wingless nymphs hatch from eggs in about 10 days and begin feeding on the tender new growth of their host plant. Nymphs resemble adults but are wingless. They can run rapidly, occasionally sideways, and hop. They develop through five stages (instars) over a period of 12 to 30 days. As nymphs grow larger, they develop wing pads. Most leafhoppers produce one generation per year, but some may develop up to six.

Species can be somewhat specific to certain host plants. As a group they feed on leaves of a wide variety of plants including many types grasses, flowers, vegetables, fruit trees, shrubs, deciduous trees, palms and weeds. The rose leafhopper, for instance, feeds primarily on plants of the rose family, although foliage of other woody plants (blackberry, oak, etc) serve as food. The potato leafhopper feeds on legumaceous plants like alfalfa, as well as on apple, birch, chestnut, maples, and others. Species in the genus, Erythroneura, feed on sycamore leaves. The six-spotted leafhopper feeds on vegetables and annual flowers. Nymphs and adults feed on the underside of leaves.

Various species feed (with sucking mouth parts) on the juices of a wide variety of plants; occasionally injuring plants and transmitting plant diseases; medically harmless although adult leafhoppers are capable of biting, temporarily producing pain. Removal of sap from the mesophyll or vascular tissues (phloem and xylem) and injection of toxic salivary secretions (e.g., proteinaceous fluid that clogs in the vascular tissues) during feeding activities cause leaves to develop yellow or clear stipples, spots or leaf portions that are visible on the upper leaf surface.