Hettes was originally expected to make his UFC debut in December 2010 as part of card; Hettes turned the offer down due to prior engagements with another promotion. On July 16, 2011, Hettes officially signed with the UFC after winning the MMA Melee - MASS Featherweight Championship Belt. As a late replacement to an injured Leonard Garcia. Hettes made his promotional debut on August 14, 2011 against Alex Caceres on 10 days notice. He won via submission at 3:12 of round 2. Hettes defeated Nam Phan on December 30, 2011 at UFC 141. Hettes used his superior judo to take Phan down repeatedly, and also utilized excellent control on the ground. He landed a great deal of unanswered ground and pound and threatened with submissions throughout, taking a dominant unanimous decision. Hettes was expected to face Steven Siler on June 22, 2012 at UFC on FX 4. However, Hettes was forced out of the bout with an injury and replaced by promotional newcomer Joey Gambino. Hettes faced Marcus Brimage on September 22, 2012 at UFC 152. He lost the fight via unanimous decision, his first professional loss. Hettes was expected to face Steven Siler on April 27, 2013 at UFC 159. However, Hettes was forced to pull out of the bout with an injury and replaced by Kurt Holobaugh. After 13 months away, Hettes returned to the UFC in October 2013. He was expected to face Mike Wilkinson on October 26, 2013 at UFC Fight Night 30. However, Wilkinson pulled out of the bout in the week leading up the bout and was replaced by newcomer Robert Whiteford. Hettes won the fight via submission in the second round. Hettes next faced Dennis Bermudez on March 15, 2014 at UFC 171. He lost the bout via TKO due to strike in the third round. Hettes was expected to face Diego Brandão on January 31, 2015 at UFC 183. However, the fight was canceled right before the event started, as Hettes passed out backstage. He was taken to a local hospital for precautionary reasons. Subsequently, the bout with Brandão was rescheduled for April 18, 2015 at UFC on Fox 15. During a back-and-forth first round, an elbow strike from Brandão opened up Hettes' cauliflower ear. The attending doctor stopped the fight between the first and second rounds, resulting in a TKO loss for Hettes. Hettes was expected to face Charles Rosa on January 17, 2016 at UFC Fight Night 81, but pulled out of the fight due to injury.
