This comprehensive discussion of agenda setting theory touches upon the merits and limitations of the theory as measured against a post-positivist yardstick. Extensions of agenda setting theory, namely policy agenda, agenda building and agenda setters are explained. Subsequently, contingency factors that influence agenda setting such as causal direction, time lag, issue obtrusiveness and the need for orientation and informational utility are also discussed. A discussion of the type of research undertaken is also included. The conclusion of this paper touches upon the possibility of other variables intervening in the development of policy agenda.