More than 20,000 species are distributed worldwide. The insects in the order have incomplete metamorphosis, and produce sound (known as a "stridulation") by rubbing their wings against each other or their legs, the wings or legs containing rows of corrugated bumps. The tympanum, or ear, is located in the front tibia in crickets, mole crickets, and bush crickets or katydids, and on the first abdominal segment in the grasshoppers and locusts. These organisms use vibrations to locate other individuals.

The use of sound is generally crucial in courtship, and most species have distinct songs. Most grasshoppers lay their eggs in the ground or on vegetation. The eggs hatch and the young nymphs resemble adults, but lack wings and at this stage are often called 'hoppers'. They may often also have a radically different coloration from the adults. Through successive moults, the nymphs develop wings until their final moult into a mature adult with fully developed wings. The number of moults varies between species; growth is also very variable and may take a few weeks to some months depending on food availability and weather conditions.

They are more active during the rain season.