A 53-year-old woman with left periorbital swelling 4 days after botulinum toxin injection in the lateral canthal area presented after noticing left eye prominence. Physical examination demonstrated proptosis and eyelid retraction. Computed tomography of the orbits confirmed extraocular muscle enlargement consistent with thyroid eye disease. In this case, the patient had development of proptosis after receiving botulinum toxin injections. Although the proptosis may represent progression of the patients' thyroid eye disease, it is worthwhile to consider incitation by botulinum toxin as a possible cause given its widespread use.