Jim Miller is an American mixed martial artist, who currently competes in the UFC lightweight division. He currently holds the record of most bouts in UFC history, most wins in UFC history, and most wins in the UFC lightweight division.

Prior to his career in mixed martial arts, Jim and his brother Dan worked in construction with their father. Since the spring of 2013 Miller has been suffering from Lyme disease, which doctors were slow to diagnose. However, since his diagnosis, Miller has been able to alleviate the symptoms of the disease by changing his nutrition plan.