Trim visible fat from the pork tenderloin. Place in a large zipper bag.
Add BBQ sauce. Seal. Shake. Refrigerate for 1-8 hours.
When ready to bake, spray a 9x13 baking pan with cooking spray. Place tenderloin in the middle of the pan.
Bake at 375 for 40-50 minutes, depending on thickness of tenderloin. In the last 10 minutes or so, you can brush on more BBQ sauce, if desired. Cook until the pork is 150 degrees internally.
Let rest 5-10 minutes before slicing.
Notes
To freeze: Prepare the marinade and pork tenderloin and place in a freezer-safe container. Freeze. When ready to prepare, defrost in the fridge, then bake as normal.