Tanglangia is an extinct genus of megacheiran arthropod that lived during the 3rd and 4th stages of the Cambrian period. The genus contains two species, T. longicaudata (the type species) and T. rangatanga, both of which are known from fossils found in the Maotianshan and Emu Bay shales respectively. The largest specimens grew up to around 3.5 cm (1.378 in) in body length.