In 1984, Niklas Luhmann published Soziale Systeme in which he applies the idea of autopoiesis (= self-production) to social systems. Abstracted from its biological connotations, the concept of autopoiesis leads to a sharp distinction between different kinds of autopoietic organization, i.e. between life, consciousness and communication. According to Luhmann, the relationship between social systems and human beings cannot be adequately analysed except by taking into account that they are environments for one another. If this theoretical background is accepted, the concepts and theory of socialization need to be revised. Luhmann takes issues with classical notions such as internalization, inculcation, or 'socialization to the grounds of consensus' (Talcott Parsons). After a historical overview of social systems research and general systems theory, it is indicated how communications trigger further communications and realize the autopoiesis of social systems. In the second part of the article, the distinction between social systems and psychic systems is used to discuss issues crucial to socialization theory. Both a revision of the concept of socialization, and lines for an empirical research programme are proposed in accordance with Luhmann's theory of social systems.