This paper discusses the concept of public opinion at a theoretical level. It starts from the recognition of the importance of this concept for sociology and reconnects with older strands in sociology and neighboring disciplines which focused on it, such as social psychology and political science. In reviewing the literature, it collects its insights and endeavours to surmount its shortcomings, drawing upon the concept of collective subjectivity. It thus tackles the theorization of public opinion regarding varied levels of centering and intentionality, social interaction, individuals and sub-collectivities, as well as the dimensions of the constitution of collective subjectivities (hermeneutic-symbolic, material, of power and space-time). Finally, the paper discusses how permanence and change take place in what regards public opinion, pointing to the mechanisms related to social memory and creativity, as well as to rhythms of social development. Evaluative and political issues relative to public opinion as a decentred collective subjecivity are also discussed.