Giant cell arteritis (GCA) is a large vessel vasculitis with variable presentations, including fevers, myalgias, headache, and jaw claudication. A particularly concerning symptom is transient vision loss, which may become irreversible without prompt recognition and treatment. The pathogenesis of GCA is incompletely understood, but it seems that the innate and adaptive immune systems play a key role in vessel inflammation, remodeling, and occlusion. We present a case of a 79-year-old male who developed GCA two days after he received his second dose of a COVID-19 mRNA vaccine. He presented with headaches, fever, and myalgias. Lab workup revealed elevated inflammatory markers, with C-reactive protein (CRP) 272 mg/L (<8.1 mg/L) and erythrocyte sedimentation rate (ESR) 97 mm/hr (0-20mm/hr). Imaging of the head, with CT and MRI, was unremarkable. His headache persisted despite supportive treatment, and he developed new, transient blurred vision, which increased suspicion for GCA. He underwent bilateral temporal artery biopsies, which were consistent with GCA. His symptoms resolved quickly with oral prednisone 60mg daily, and his inflammatory markers returned to normal within a month. A review of the literature revealed several case reports of giant cell arteritis following influenza vaccination. However, no large-scale studies have demonstrated a causal relationship between GCA and immunization. Our case demonstrates the first instance of GCA following a COVID-19 mRNA vaccine. We propose that the upregulated immune response to the vaccine acted as a trigger for GCA in this patient with predisposing factors. While causation cannot be determined based on one case alone, our case demonstrates an opportunity for further research into the relationship between vasculitis and immunizations. Despite this isolated case, the proven benefits of COVID-19 mRNA vaccines significantly outweigh any theoretical risk of immune dysregulation following administration.