Tom Brady's run in the NFL has officially come to an end ... the quarterback revealed Wednesday morning he's retiring -- and this time, it's "for good."

The Tampa Bay Buccaneers star made the announcement in a short video that he posted to his social media page.

In the clip, Brady fought back tears -- while insisting there's no chance he comes back to the gridiron again.

"I know the process was a pretty big deal last time," Brady said, "so when I woke up this morning I figured I'd just press record and let you guys know first."

Tom went on to thank his family, friends, teammates, opponents and fans -- adding that he "wouldn't change a thing."

"Love you all," he concluded.

Brady's made this announcement once before -- back on Feb. 1 of last year, he told the football world he was done. Of course, that retirement lasted just a few weeks, as he unretired just 40 days later.

Tom's contract with the Bucs had run out this offseason -- but many had speculated the 45-year-old could return in 2023, perhaps with the Super Bowl contender San Francisco 49ers.

But, Brady -- who played 23 seasons in the NFL -- made it clear in his vid Wednesday, he ain't coming back.

Tom appeared at peace with this decision at the "80 For Brady" premiere on Tuesday in Los Angeles, sporting a big smile while rubbin' elbows with his costars and other Hollywood celebs.

Brady will go down as arguably the greatest football player ever -- his resume is unmatched ... he won seven Super Bowls, earned three MVP awards, and was selected to 15 Pro Bowls. He was also named an All-Pro three times ... and threw for 89,214 yards and 649 TDs -- both NFL records.

In his final season in the league, Brady led the Bucs to the playoffs -- but bowed out early, losing to the Dallas Cowboys in the Wild Card round.

He's now expected to hit the broadcast booth after signing a mega deal to work with Fox as a color commentator.