The hallmark of diffusion of innovations theory is that it deals with dissemination of new ideas and adoption by people in a systematic manner. Diffusion of innovations theory is an effective tool for social change. The diffusion of innovations theory deals with dissemination of an innovation as an idea, practice, or product (including services) perceived as new by an individual or other unit of adoption. The innovation-decision process (Rogers, 2003) is a five step process: (1) gaining knowledge about the innovation; (2) becoming persuaded about the innovation; (3) decision step of adopting or rejecting the innovation; (4) implementation step of putting the innovation to use; and (5) confirmation step of either reversing the decision or adopting the new innovation. The applications of the diffusion of innovations theory in public health, health promotion, and health education began with immunization campaigns and family planning programs. Its application in alcohol, tobacco, and drugs can be seen at two levels. The first level pertains to adoption and diffusion of the habit of using alcohol, tobacco, and drugs. The second level pertains to diffusion of successful interventions pertaining to prevention and control of alcohol, tobacco, and drugs. However, there are some limitations to the diffusion of innovations theory that researchers must consider.