Ortiz vs. Shamrock 3: The Final Chapter was a mixed martial arts event held by the Ultimate Fighting Championship on October 10, 2006. The event took place at the Seminole Hard Rock Hotel and Casino in Hollywood, Florida and was broadcast live on Spike TV in the United States and Canada. The two-hour broadcast drew a 3.1 overall rating, with the main event of Tito Ortiz vs. Ken Shamrock 3 drawing a 4.3 rating. Quoting MMA Weekly's Ivan Trembow, "That breaks down to an amazing 5.7 million viewers for the Ortiz vs. Shamrock fight. This shatters the UFC's previous record for the number of people watching a UFC fight at any given time." The overall ratings record would not be matched until UFC 75 on September 8, 2007.
The main event featured the third and final encounter between Tito Ortiz and Ken Shamrock. At UFC 61, the two fighters met for a second time, with Ortiz reigning victorious via technical knockout; however, critics contend that the fight was stopped too early by referee Herb Dean. At the UFC 62 weigh-ins, UFC President Dana White announced the third Ortiz-Shamrock encounter. Tickets went on sale on Tuesday, August 29, and sold out very quickly in two days.