Theodore A. Atlas Jr. (born July 29, 1956) is an American boxing trainer and fight commentator.

The son of a doctor, Atlas grew up in a wealthy area of Staten Island, New York City, New York. His mother, Mary Riley Atlas, was a former contestant in the Miss America pageant system, as well as a model. His father was of Hungarian Jewish ancestry and his mother of Irish descent. Atlas was raised in his mother's Catholic faith and spent summers in Spring Lake, New Jersey, with his family's friends.

By his own admission, Atlas had a somewhat troubled, rebellious youth. He dropped out of school and was arrested several times. He participated in an armed robbery and served time on Rikers Island. Atlas was involved in a street fight in Stapleton, Staten Island, in which his face was severely slashed with a "007" pocketknife. The wound took 400 stitches in total to close, with 200 on the outside of his face and 200 on the inside. The attack left him with a distinctive scar.

Atlas trained as an amateur boxer with Hall of Fame trainer Cus D'Amato. He had some amateur fights and won a 135-pound Golden Gloves title but had to turn to work as a trainer due to a back injury. Atlas was an assistant to D'Amato, although his role in the Catskill Boxing Club was short-lived. In 1980 he trained Sweden Olympic Boxing Team for 1980 Summer Olympics. His duties included assisting in the training of D'Amato's teenage protégé Mike Tyson. However, Atlas left the camp in 1982 following an altercation with the 15-year-old Tyson after Tyson had been sexually inappropriate with an 11-year-old female relative of Atlas' (Tyson said he had grabbed the girl's buttocks). Atlas put a .38 caliber handgun to Tyson's ear and told him to never touch his family again, or he would kill him if he did. This altercation between Atlas and a young Mike Tyson led to Atlas' dismissal from the Catskill Boxing Club, and he was told he was no longer welcome in D'Amato's home or around any of his adopted children (his fighters whom he had legally adopted, Tyson included).

Atlas enjoyed his biggest success as head trainer to Michael Moorer, whom he guided to the world heavyweight title in 1994. He drew criticism for what some considered to be overly dramatic speeches in the ring corner, particularly during Moorer's heavyweight title fight with Evander Holyfield, and some felt he did this to draw attention to himself rather than help his fighter. During one such speech, Atlas blocked Moorer from sitting on his stool and asked, "Do you want me to take over?" Atlas has denied this, stating that he did what he believed the fighter needed based on his understanding of the fighter. Moorer went on to defeat Holyfield by a majority decision, with Moorer's manager John Davimos crediting Atlas' motivation, stating "I don't know if Michael could have done this without Teddy Atlas."

Atlas also worked the corners of featherweight world champion Barry McGuigan in one fight and light heavyweight Donny Lalonde. Lalonde was a top-ranked boxer and went 8–0 with Atlas as his trainer, but they clashed in temperament and style. "He ran things like an army camp," Lalonde said, "I'm more of a free spirit." Lalonde also said it was a waste of time in his career. He and Atlas parted ways, and Lalonde hired Tommy Gallagher as his new trainer. In his autobiography, Atlas claimed he was so angry at having been fired by Lalonde that he went to Lalonde's house with a gun intending to kill him. However, Lalonde refuted Atlas' story, claiming he did not even live at the apartment Atlas described at the time. Lalonde also called Atlas "the least significant of all my trainers throughout my career."

In 2009, Atlas began training Russian heavyweight Alexander Povetkin as Povetkin prepared for an eventual title match against Wladimir Klitschko. Povetkin was a former world amateur champ and was the number one contender. Atlas said that Povetkin "wasn't ready" for Klitschko

In 2015, Atlas returned to training to prepare Timothy Bradley for his welterweight title defense against Brandon Rios. With Atlas in his corner, Bradley knocked out Rios in the ninth round of their fight, which took place on November 7, 2015, in Las Vegas.