今颚总目（学名Neognathae），具有充气性的骨骼，龙骨突发达，左右锁骨下端愈合，称之为叉骨，尾综骨发达。体表有羽区跟裸区的差别，正羽发达，形成羽片。翼有发达的飞羽，善飞翔，大多两性或是雌性孵化，雄鸟一般不具外交配器官。雏鸟为早成或是晚成熟鸟。世界性分布，世界现存的鸟类大多属于本总目。

Neognaths (Neognathae) are birds within the subclass Neornithes of the class Aves. The Neognathae include virtually all living birds; exceptions being their sister taxon (Palaeognathae), which contains the tinamous and the flightless ratites.

There are nearly 10,000 species of neognaths. Since the late Cretaceous period, from which the earliest fossils are known, they have undergone adaptive radiation producing the diversity of form, function, and behavior that we see today. It includes the order Passeriformes (perching birds), the largest clade of land vertebrates, containing some 60% of living birds and being more than twice as speciose as rodents and about five times as speciose as Chiroptera (bats), which are the largest clades of mammals. There are also some very small orders, usually birds of very unclear relationships like the puzzling hoatzin.