Abies × borisii-regis (Bulgarian fir) is a hybrid species of fir native to the mountains of the Balkan Peninsula in Bulgaria, northern Greece, Kosovo, North Macedonia, Albania and Serbia.

[1] It occurs at altitudes of 800–1,800 m (2,600–5,900 ft), on mountains with an annual rainfall of over 1,000 mm (39 in).

The leaves are needle-like, flattened, 1.8–3.5 cm (0.71–1.38 in) long and 2 mm (0.079 in) wide by 0.5 mm (0.020 in) thick, glossy dark green above, and with two blue-white bands of stomata below.

The cones are 10–21 cm (3.9–8.3 in) long and 4 cm (1.6 in) broad, with about 150–200 scales, each scale with an exserted bract and two winged seeds; they disintegrate when mature to release the seeds.

[2][3][4][5][6] The scientific name honours Tsar Boris III of Bulgaria, during whose reign it was described as a new species in 1925.