Great Green Bush-Cricket, is a species of 'katydids crickets' belonging to the family Tettigoniidae subfamily Tettigoniinae. Females are bigger than the males and reach 32–42 millimetres. Tettigonia viridissima is distinguished by its very long and thin antennae, which can sometimes reach up to three times the length of the body, thus differentiating them from grasshoppers, which always carry short antennae. The female has an egg-laying organ (ovipositor) that can reach a length of 23 to 32 23–32 millimetres (0.91–1.3 in).
This species can be encountered from the Europe to Mongolia, especially in meadows, grasslands, prairies and occasionally in gardens.