Females of Araniella cucurbitina are larger than males. Moreover the male is generally much slimmer, with more developed limbs (Sexual dimorphism). In fact females grow up to 4.5–9.5 millimetres (0.18–0.37 in), while males only up to 3.5–4.5 millimetres (0.14–0.18 in). Adult spiders in Spring show a basic green color. The cephalothorax (prosoma) is light yellowish to red-brown, but the abdomen (opisthosoma) is definitely green or yellowish green, with four pairs of black lateral spots.
The legs are yellowish green or yellow-red-brown. On the lower end of the abdomen there is a red mark. At the extremities of the pedipalps, males have the copulatory organs, called palpal bulbs, similar to an ampoule, that are used to transfer sperm to the female. Freshly hatched spiderlings are red, and change to brown before the autumn.
Araniella opisthographa is an almost identical spider which can only be distinguished from A. cucurbitina by
a microscopic investigation.