Horseshoe lung (HL) is often associated with cardiovascular malformations such as scimitar syndrome and unilateral lung hypoplasia. In patients with HL, the hypoplastic lung is almost always located on the right side. Cases of HL with a hypoplastic left lung are extremely rare. In this paper, we describe a case of a one-day-old boy with HL involving left lung hypoplasia and perform a systematic review of the literature on HL with left lung hypoplasia. Only 10 cases of HL involving left lung hypoplasia have been reported in the literature. Most of those cases also exhibited cardiovascular malformations and pulmonary hypertension. There have not been any reported cases of HL involving left lung hypoplasia associated with scimitar syndrome. HL involving left lung hypoplasia is rare and tends to be associated with pulmonary hypertension.