Allodelphinidae was named by Barnes (2006) [A family of the odontocete superfamily Platanistoidea having cranium with elongate and narrow rostrum; rostrallength more than four times braincase length; premaxillae and maxillae both reaching anterior rostral extremity; premaxillae and maxillae fused together distally; mesorostral groove open dorsally on at least posterior part of rostrum; anteroposteriorly elongated groove present on lateral side of rostrum approximately following maxilla/premaxilla suture; facial region around dorsal narial opening and cranial vertex elevated in sagittal plane and sloping laterally onto supraorbital processes; posterior maxillary foramen located posterolateral to external naris and not close to posterior end of premaxilla; posterolateral sulcus on premaxilla shallow and not enlarged; posterior end of premaxilla irregularly-shaped, thin dorsoventrally, and narrow (not expanded transversely); nasals elongate anteroposteriorly and narrow transversely; nuchal crest thickened anteroposteriorly and elevated; lateral lamina of pterygoid present (formed as an outer lamina or bony plate of pterygoid within orbit), extending posteriorly from palate and contacting styliform process of squamosal; zygomatic process of squamosal not expanded dorsoventrally, not compressed transversely, and glenoid fossa facing anteroventrally; no fossa for posterior sinus present within anterior surface of paroccipital process; tympanic bulla with elongated and pointed anterior spine, with thin outer lip that is smoothly over-arching and high relative to transverse width of bulla; mandible with symphyseal portion narrow, anteroposteriorly elongated, and dorsoventrally compressed; mandibular symphysis firmly ankylosed; all teeth single-rooted; cervical vertebrae large and with anteroposteriorly elongated centra; atlas vertebra bearing both dorsal and ventral transverse processes; thoracic vertebrae not greatly enlarged; lumbar vertebrae large and with anteroposteriorly elongate centra; caudal vertebrae enlarged; humerus with diaphysis proximo-distally elongate and oval in cross section; humeral head large and ovoid-shaped; propensity for humerus to non-pathologically fuse to ulna.].

It was assigned to Platanistoidea by Barnes (2006), Barnes and Reynolds (2009), Aguirre-Fernández and Fordyce (2014), Boersma and Pyenson (2016), Marx et al. (2016), Kimura and Barnes (2016), Berta (2017) and Viglino et al. (2022).