Male Anthony's nightjars weigh 32.3 to 39.5 g (1.1 to 1.4 oz) with a mean of about 35 g (1.2 oz) and females 31.0 to 42.0 g (1.1 to 1.5 oz) with a mean of about 37 g (1.3 oz). Males have grayish brown upperparts with buff speckles and blackish brown streaks; the crown is darker. They have a broad tawny buff collar on the nape. The tail feathers are mostly brown with considerable white on the outermost pair. The chin and upper throat are tawny buff with dark brown bars and speckles. The lower throat is white, the breast grayish brown with buff bars, and the belly and flanks buff with faint brown bars. In flight the five outermost primary wing feathers show a white or buffy stripe. The female is similar to the male but with less white on the wings and tail.
Anthony's nightjar is found in coastal western Ecuador into northern Peru. It is generally sedentary but may make small movements in response to rains. It inhabits arid open woodlands, grasslands, and shrublands. In elevation it ranges from sea level to 800 m (2,600 ft).
Anthony's nightjar is active from dusk to dawn. It roosts on the ground during the day and is usually solitary.
Though Anthony's nightjar is active throughout the night, it does most of its foraging at dusk and in early evening. It captures its insect prey in flight or by sallying from a branch. It tends to forage over open or semi-open areas.
The breeding season of Anthony's nightjar has not been defined, though it appears to be concentrated between December and March and be tied to rainfall. It lays its single egg on the ground atop leaf litter.
The IUCN has assessed Anthony's nightjar as being of Least Concern. Its population is unknown but believed to be increasing, perhaps in response to the clearing of forest and dense scrub.