The Green-crowned Brilliant has the most northerly range of the Heliodoxa species (del Hoyo et al. 1999). It occurs from northern Costa Rica to western Ecuador, with intervening populations in Panama and Colombia.
In Costa Rica, it is found in the Cordillera de Guanacaste, Cordillera de Tilarán, Cordillera Central and Cordillera de Talamanca, mainly on the Caribbean slope, but also locally on the Pacific slope (Stiles and Skutch 1989).
In Panama, the species has been recorded in the provinces of Chiriquí (where it is rather scarce on the slopes of Volcán Barú), Bocas del Toro, Veraguas, western Coclé, eastern Panama province, western San Blas, and eastern Darién (Ridgely and Gwynne 1989).
In Colombia, the species is known from Cerro Tacarcuna, the extreme northern ends of the Western Andes and Central Andes, the eastern slope of the Central Andes in Caldas department, and both slopes of the Eastern Andes in Cundinamarca department (Hilty and Brown 1986). It is also a rare inhabitant of the foothills of Nariño department in the southwest of the country (Salaman and Mazariegos H. 1998). The presence of an apparent hybrid of the Green-crowned Brilliant and Fawn-breasted Brilliant at Reserva Natural Tambito in the lower montane zone of Cauca department, also in the southwest, suggests that H. jacula jamesoni occurs in the vicinity (Donegan and Dávalos 1999).
In Ecuador, it occurs on the western slope of the Andes, from Esmeraldas province in the north to the very south of El Oro province at least, and locally on the slopes of the coastal cordilleras of Chindul, Mache and Colonche (Ridgely and Greenfield 2001).