This species is present in the Palearctic realm (from Europe to Siberia and Sakhalin, Kazakhstan, Caucasus) and in the Nearctic realm (Canada and United States of America).

[3][2] Psylla alni can reach a body length of about 5–6 mm (0.20–0.24 in).

These rather large psyllids have a green head, body, and legs, and rather long antennae.

Adults are initially green, later becoming orange, brown, or reddish.

[4] In the 5th preimaginal stage nymphs can reach a length of about 2–3 mm (0.079–0.118 in).