Abstract Late Smithian (Early Triassic) ammonoids from a single carbonate concretion in the uppermost Lusitaniadalen Member ( Fish Niveau , Vikinghøgda Formation) at Stensiöfjellet, Spitsbergen, are studied and compared with similar assemblages from other areas. Late Smithian ammonoid assemblages are characterised worldwide by low diversity and predominance of the family of the prionitids. The species identified here are: Wasatchites tridentinus, Wasatchites cf. distractus, Anasibirites kingianus, Arctoprionites nodosus, Arctoprionites resseri and Xenoceltites subevolutus. The group named Wasatchites spp. indet. includes juveniles of the genus Wasatchites which were hard to identify at species level. Two new taxa are proposed: Arctoceras sp. nov and Gen. et sp. nov. (prionitid). Difficulties in taxonomic identification have arisen due to the high intraspecific variation and the immature stage of most of the specimens. The assemblage is discussed in a broader context to infer information about the ecological, biostratigraphic and palaeogeographic implications. The good preservation and lack of evidence of transportation suggest deposition in a low energy environment, in accordance with sedimentological observations. The lack of true juveniles and adult individuals may indicate separation of the groups until maturity and high juvenile mortality. From a biostratigraphic point of view, the Spitsbergen fauna is in good agreement with other assemblages within and outside the Boreal Realm. Most similarities, as already pointed out in previous literature, are with the Boreal Canadian Province, though the studied fauna seems to present some peculiarities. The presence of newly recorded taxa such as Wasatchites cf. distractus and Arctoprionites resseri that are more typical for lower latitudes may suggest more marked connections with warmer water than expected (in a similar fashion as in Canada). The finding of arctoceratids at this level confirms their range up to the tardus Zone.