Place asparagus in a large shallow bowl. Sprinkle with lemon juice, olive oil and minced garlic, tossing to coast. Sprinkle on lemon zest, then season with salt and pepper.
Divide the asparagus between two large squares of aluminum foil. Wrap up the foil, pinching the ends to seal.
Place foil packets on the grill, directly over flame. Grill for 10 to 20 minutes, depending on thickness of asparagus, or to desired doneness.