The date of the interview was not immediately known. Thibodeau has spent 19 years as an NBA assistant coach, including a previous two-year stint with the Sixers in the 1990s, and just completed his second season on the Celtics staff. With Boston's season over after a Game 7 elimination against Orlando, Thibodeau was free to talk with the Sixers.
Thibodeau is known as a defensive specialist and was on New York's staff when the Knicks set a then-NBA record by holding 33 consecutive opponents under 100 points in the 2000-01 season.
The Sixers interviewed former Wizards coach Eddie Jordan on Friday. He's the only known candidate to have interviewed with Sixers president Ed Stefanski. The Philadelphia job became vacant when Tony DiLeo stepped down last week and returned to the front office.
Philadelphia went 41-41 and was eliminated in six games by the Orlando Magic. It was the second straight season the Sixers were eliminated in the first round of the playoffs.
The Sixers are not commenting on the coaching search. Stefanski said last week the search was wide open.
"You look at assistants, you look at head coaches, you look at everything," he said.