Prepare a grill for medium heat. If using a charcoal grill, build an even layer of hot coals on the bottom and remove the ring if it has one so the coals are exposed.
Prepare the foil packets: Lay out a double layer of large heavy-duty aluminum foil pieces in an X formation, totaling 2 packets.
Distribute the peaches, cut side down, 2 tablespoons of the honey and the butter evenly between the packets.
Bring up all 4 sides of the foil, but don't seal. Grate the lemon zest evenly between each packet. Squeeze the lemon juice evenly between each packet.
Tightly seal the foil. Place the packets directly on the grill, or onto the coals (if using charcoal grill) and cook until the peaches are tender and cooked through, 10 to 12 minutes (if peaches are ripe), 20-25 minutes (it peaches are not yet ripe).