Defective Bi2Te3 structures have been studied with the aim of lowering the thermal conductivity in order to improve the thermoelectric figure of merit. The cross-plane thermal conductivities of structures containing point defects have been computed by means of molecular dynamics techniques, finding a maximum decrease of 70% for a 4% concentration of tellurium atom vacancies. Superlattices with modified stoichiometries have also been considered in order to find the configuration having the lowest thermal conductivity. In this case, a maximum decrease of 70% was also found. These predictions open the way to the design of efficient bulk thermoelectric materials having optimised thermal properties similar to those of superlattices.