Hypokalemic periodic paralysis occurring in thyrotoxicosis is rare in Caucasians and is not often highlighted as an endocrine emergency. Periodic paralysis, without familial background, manifests only in the thyrotoxic patient. Thyrotoxic periodic paralysis is a self-limiting disorder that is cured by the treatment of the underlying hyperthyroidism. We report an unusual case of acute onset weakness from thyrotoxic periodic paralysis in a young Chinese migrant who had a normal serum potassium level at the time of initial presentation, though on subsequent presentation one week later, he had the typically associated hypokalemia. We also review the literature on thyrotoxic periodic paralysis.