Kai L. Greene (born July 12, 1975) is a professional bodybuilder. His most recent victory was the Prague Pro in 2013. Greene was the first runner up (2nd Place) at the 2012 and 2013 Mr. Olympia competition.

In 2011, Greene began working with preparation coach George Farah and placed first in the 2011 New York Pro Championship. Greene's third place win at Mr. Olympia in 2011 qualified him for the 2012 contest in Las Vegas, hence he did not compete at the 2012 New York Pro in order to focus on Mr. Olympia. On September 29, 2012, Greene placed 2nd in the 2012 Mr. Olympia competition. On September 28, 2013, Kai placed 2nd again in the 2013 Mr. Olympia competition in Las Vegas, Nevada.