It's Veteran's Day ... and NFL star Pierre Garcon is giving back in a pretty awesome way -- WITH FREE PIZZA!!!
The Washington Redskins wide receiver is offering free slices to military vets at the SpinFire Pizza restaurant he owns in Ashburn, Virginia.
We're told several of Pierre's teammates are at the restaurant RIGHT NOW taking pics with fans and hanging with military vets ... including Robert Griffin III.
Pretty cool, right?