Giant cell arteritis (GCA) is a granulomatous vasculitis that targets medium and large sized vessels. Binocular diplopia has been reported in a small number of patients with visual manifestations of GCA. It can be caused by ischaemia in any segment of the ocular motor system including the brainstem, ocular motor cranial nerves, or extraocular muscles. Diplopia can be associated with other ocular and systemic symptoms, such as blurred vision, eye pain, headaches, jaw claudication, and scalp tenderness. More importantly, it can accompany transient or permanent vision loss and could be used as a warning sign for other complications. The goal of this retrospective study was to determine the population-based rates and patterns of binocular diplopia from GCA. The Rochester Epidemiology Project (REP), a medical records linkage system was used to identify all residents of Olmsted County, Minnesota, USA, diagnosed with GCA between 1 January 1950 and 31 December 2019. Medical records were then reviewed to identify patients with binocular diplopia from GCA. There were 301 incident cases of GCA from 1950 to 2019. Fourteen (5%) patients presented with binocular diplopia. Of these 14 patients, nine (3%) had constant diplopia and five (2%) had transient diplopia. Among patients with constant diplopia, cranial nerve VI involvement was suspected in four (44%) cases. Systemic symptoms and inflammatory markers were similar in patients with and without diplopia. There was no difference in the rate of anterior ischaemic optic neuropathy between the two groups (7% versus 7%, p=1.00). In conclusion, this population-based study showed that binocular diplopia was present in 5% of patients with GCA, which could either be transient or constant. GCA patients with diplopia had similar systemic manifestations and risk of vision loss as GCA patients without diplopia. This study has several limitations including its retrospective design and a predominantly white Caucasian population bias. However, due to GCA being a potentially blinding disease, a high index of suspicion is required. The authors suggest that elderly patients presenting with binocular diplopia should undergo further workup for systemic symptoms and inflammatory markers suggestive of GCA.