A high-integrity pressure protection system Christmas tree is provided. In one embodiment, an apparatus includes a Christmas tree, a choke coupled to receive fluid from the Christmas tree, and a high-integrity pressure protection system. The high-integrity pressure protection system includes pressure sensors downstream of the choke, valves upstream of the choke, and a logic solver connected to control operation of the valves of the high-integrity pressure protection system that are upstream of the choke. Further, the valves of the high-integrity pressure protection system that are upstream of the choke include at least two valves of the Christmas tree. Additional systems, devices, and methods are also disclosed.