Do I still owe a lender a fee if I'm approved for financing but never end up drawing on it?

Possibly, and whether a fee applies depends entirely on the specific terms of the commitment letter or loan agreement, not on whether the funds are actually drawn. Many commercial commitment letters and loan agreements include a commitment fee, or standby fee, payable simply for the lender approving the facility and making funds available or reserving capacity for the buyer, separate and distinct from the interest that only begins accruing once amounts are actually drawn down.

This kind of fee exists because a lender ties up its own capacity and takes on administrative and opportunity cost by approving and holding a facility open, whether or not the borrower ultimately uses it, so it is not treated as conditional on drawing the funds unless the specific agreement says otherwise. A buyer who is genuinely unsure whether they will need the approved financing, for example because they are also exploring a vendor take-back or other funding source, should check this specific term in the commitment letter before assuming that simply walking away from unused financing carries no cost.