Leivanectes is a genus of plesiosaurs of the family Elasmosauridae known from Late Aptian marine deposits in central Colombia. It contains a single species, L. bernadoi, which was described in 2019.
Leivanectes differs from Callawayasaurus, which has been found in the same formation, in having fewer mandibular alveoli and a short mandibular symphysis with three alveoli (5 in Callawayasaurus).
Leivanectes remains have been found in the fossiliferous Paja Formation of the Altiplano Cundiboyacense, which crops out near Villa de Leyva, also written as Villa de Leiva, Boyaca, Colombia. The genus name refers to Villa de Leiva.