[3] The brown booby was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in his Histoire Naturelle des Oiseaux in 1781.

[4] The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text.

[5] Buffon did not include a scientific name with his description but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Pelecanus leucogaster in his catalogue of the Planches Enluminées.

[9] In 2024, the subspecies brewsteri and etesiaca were declared a distinct species by the name Cocos booby by the American Ornithological Society, Clements Checklist, and the IOC World Bird List.

There are two recognised subspecies:[10] The booby's head and upper body (back) is covered in dark brown to blackish plumage, with the remainder (belly) being a contrasting white.

[3] They are grey-brown with darkening on the head, upper surfaces of the wings and tail, while the lower breast and underpart plumages are heavily flecked brown on white.