The laughing falcon is 46 to 56 cm (18 to 22 in) long and has a wingspan of 79 to 94 cm (31 to 37 in).
 As usual among birds of prey, the females are bigger, weighing 600 to 800 g (1.3 to 1.8 lb) compared to the males' 410 to 680 g (0.90 to 1.50 lb).

Adults have a pale buff head, changeable between a more brownish and an almost white hue according to feather wear and individual variation.
The broad black face mask stretches across the neck as a narrow collar, bordered with white.
On the crown, the feather shafts are dark, producing a somewhat streaked effect.
The upper wings and back are blackish brown.
The uppertail coverts are whitish buff again, and the rectrices are barred black and whitish, ending in white.
The underside is uniformly pale buff; there may be a bit of dark speckling on the thighs, however.
The underside of the wing is pale rufous-buff, sometimes with some dark spotting on the underwing coverts.
The tips of the primary remiges are barred with pale grey below, their bases are quite rufous.
The iris is dark brown, the bill is black with a pale yellow cere; the feet are also pale yellow.

Immature birds differ little from adults; they have lighter margins to the back feathers, producing a scalloped effect.
The light parts of the plumage are almost white, paler than in adults; the unfeathered parts are also paler.
Nestlings are covered in peculiarly dense down, reminiscent of a duckling's; they are generally brownish buff, darker above, and already show the blackish facial marks of the adults.

With its big white (immature) or pale buff (adult) head having a dark brown mask from the eyes around to the nape, it is unmistakable.
In flight it shows a rufous patch near each wingtip (formed by the basal parts of the primaries) and a shape more like an Accipiter hawk than most of its falcon relatives, with short, rounded wings and a long tail.
The laughing falcon is 46 to 56 cm (18 to 22 in) long and has a wingspan of 79 to 94 cm (31 to 37 in).  As usual among birds of prey, the females are bigger, weighing 600 to 800 g (1.3 to 1.8 lb) compared to the males' 410 to 680 g (0.90 to 1.50 lb).
Adults have a pale buff head, changeable between a more brownish and an almost white hue according to feather wear and individual variation. The broad black face mask stretches across the neck as a narrow collar, bordered with white. On the crown, the feather shafts are dark, producing a somewhat streaked effect. The upper wings and back are blackish brown. The uppertail coverts are whitish buff again, and the rectrices are barred black and whitish, ending in white. The underside is uniformly pale buff; there may be a bit of dark speckling on the thighs, however. The underside of the wing is pale rufous-buff, sometimes with some dark spotting on the underwing coverts. The tips of the primary remiges are barred with pale grey below, their bases are quite rufous. The iris is dark brown, the bill is black with a pale yellow cere; the feet are also pale yellow.
Immature birds differ little from adults; they have lighter margins to the back feathers, producing a scalloped effect. The light parts of the plumage are almost white, paler than in adults; the unfeathered parts are also paler. Nestlings are covered in peculiarly dense down, reminiscent of a duckling's; they are generally brownish buff, darker above, and already show the blackish facial marks of the adults.
With its big white (immature) or pale buff (adult) head having a dark brown mask from the eyes around to the nape, it is unmistakable. In flight it shows a rufous patch near each wingtip (formed by the basal parts of the primaries) and a shape more like an Accipiter hawk than most of its falcon relatives, with short, rounded wings and a long tail.
Laughing falcon