Robert Alexander McCullough IV (born May 26, 1977) is an American former Muay Thai kickboxer and professional mixed martial artist.

McCullough began his mixed martial arts career with a first-round TKO victory at the Palace Casino in Lemoore, California, in 2001.

McCullough defeated Isaac de Jesus by first-round TKO on July 9, 2010, at Tachi Palace Fight 5.

He then defeated UFC veteran Corey Hill by unanimous decision on September 9, 2010, at Tachi Palace Fight 6.

[10] On October 14, 2010, McCullough signed with Bellator to compete in the promotion's upcoming Season Four Lightweight Tournament.