Acipenseriformes /æsɪˈpɛnsərɪfɔːrmiːz/ is an order of basal[1] ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct families Chondrosteidae and Peipiaosteidae.

[5] Members of Acipenseriformes retain the ability to sense electric fields (electroreception) using structures called ampullae.

[5] The ancestors of Acipenseriformes are thought to have split from those of other living fish around the Carboniferous period (360–300 million years ago).

[10] The oldest unambiguous members of the order are the Chondrosteidae, a group of large fish found in marine deposits from the Early Jurassic (201–175 million years ago) of Europe, which already have reduced ossification of the skeleton.

A study published in 2020 reported a successful hybridization between a Russian sturgeon (Acipenser gueldenstaedtii) and an American paddlefish (Polyodon spathula), indicating that the two species can breed with one another despite their lineages having been separated for hundreds of millions of years.