No, it is not the same; they are two different cuts of meat. A pork loin is a wide, thick, rectangular cut of meat from the pig's loin muscle, which runs from the shoulder to the rear. Pork tenderloin is a long, narrow, lean, and tender cut of meat from near the top of the pig, opposite the loin.  Because of their different sizes, pork loin and pork tenderloin aren't interchangeable in recipes.