Chapter 5 reviews social psychological theories of persuasion and research, and their applications to understanding advertising effects. We categorize the theoretical development into four stages. Stage 1 theories (e.g. information processing model) assume that persuasion involves learning of arguments contained in a communication. The failure to find recall of message arguments related to extent of persuasion disproved such models. In Stage 2, the cognitive response theory replaced the passive learner of arguments with an active respondent, who responds with supportive or counterarguments. In Stage 3, dual process theories abandon the assumption that acceptance of message arguments have to be based on a systematic processing. Recipients who are unable or unmotivated to systematically process a message rely on heuristic cues (e.g. communicator credibility, country-of-origin information). In Stage 4 the unimodel abandons the necessary link between extent of processing motivation/ability and type of cue used. The second part of this chapter reviews strategies advertisers use to deal with two of the major shortcomings of advertising, namely that consumers try to avoid exposure to advertisements and that knowledge of the persuasive intent of advertisements triggers resistance to persuasion.