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. It occurs at elevations of , on mountains with an annual rainfall of over .
alt=|left|thumb|Abies borisii-regis in the [[Pirin Mountains, Bulgaria]]
It is a large evergreen coniferous tree growing to (exceptionally ) tall and with a trunk diameter of up to . The leaves are needle-like, flattened, long and wide by thick, glossy dark green above, and with two blue-white bands of stomata below. The tip of the leaf is variable, usually pointed, but sometimes slightly notched at the tip, particularly on slow-growing shoots on older trees. The cones are long and broad, with about 150–200 scales, each scale with an exserted bract and two winged seeds; they disintegrate when mature to release the seeds.