Avisauridae is a family of extinct enantiornithine dinosaurs from the Cretaceous period, distinguished by several features of their ankle bones.

As a result, members of this family are distinguished from other enantiornithines exclusively by features of the tarsometatarsal and pedal phalanges (toe bones).

Unlike in some prehistoric birds, avisaurid tarsometatarsals were not completely fused, with the distal (outer) parts of the metatarsals being separate from each other.

The inside edge of this bone's trochlea (toe joint) has a bony tab which points downward, known as a plantar projection.

[4][2] Chiappe and Calvo (1994) found that the Avisauridae shared adaptations of the foot — including a fully reversed and distally placed hallux with a large claw — that indicated the ability to perch in trees.

[7] However, Chiappe later reassigned the Avisauridae to the class Aves (which is equivalent to the clade Avialae in modern usage) and the subclass Enantiornithes in 1992.