Will tail lights for a 2001 Ford Explorer fit on sport?

Generally, yes, the taillights for a 2001 Ford Explorer will fit a 2001 Ford Explorer Sport. The Sport is just a trim level, not a significantly different body style. However, there's always a small chance of minor variations depending on specific options (like towing packages).

To be absolutely certain, check the part numbers. Compare the part numbers of the taillights you intend to buy with the part numbers of your existing taillights. You can find your taillight part numbers on the lights themselves or in your owner's manual. You can also use online auto parts stores to cross-reference part numbers.