Laser-assisted phosphorus doping is demonstrated on ultrathin transition-metal dichalcogenides (TMDCs) including n-type MoS2 and p-type WSe2. Temporal and spatial control of the doping is achieved by varying the laser irradiation power and time, demonstrating wide tunability and high site selectivity with high stability. The laser-assisted doping method may enable a new avenue for functionalizing TMDCs for customized nanodevice applications.