Advertising and public relations enjoy a prime spot in marketing communication. They are used as persuasive and communication tools that target specific publics. Advertising leverages messages paid for by identifiable sponsors in media vehicles, but public relations employs strategic information provision to the media which are treated as news.  Public opinion, on the other hand, is an aggregation of individual views, attitudes, and beliefs about an issue as expressed by the majority of people. The impact of advertising and public relations on the shaping of public opinion (about products, services, and ideas, policies, etc.) is established in literature and discourses. However, advertising and public relations practitioners often rely on their creativity and communication skills, oblivious of how much public opinion affects advertising and public relations efforts. This has led to monumental marketing communication failures and waste of budgets. This paper considered the interplay between advertising, public relations and public opinion. The authors draw from various theoretical frameworks and contemporary events in marketing, politics, and social management to establish the correlation between both phenomena. They insist that marketing communicators, in trying to shape public opinion, must factor in public opinion in the preparation of their messages.         
Keywords: Advertising, Attitude, Communication, Public Opinion, Public Relations