Professionalization is the social process by which any trade or occupation transforms itself into a true "profession of the highest integrity and competence." This process tends to involve establishing acceptable qualifications, a professional body or association to oversee the conduct of members of the profession and some degree of demarcation of the qualified from unqualified amateurs. This creates "a hierarchical divide between the knowledge-authorities in the professions and a deferential citizenry." This demarcation is often termed "occupational closure", as it means that the profession then becomes closed to entry from outsiders, amateurs and the unqualified: a stratified occupation "defined by professional demarcation and grade." The origin of this process is said to have been with guilds during the Middle Ages, when they fought for exclusive rights to practice their trades as journeymen, and to engage unpaid apprentices.

Professions also possess power, prestige, high income, high status and privileges; their members soon come to comprise an elite class of people, cut off to some extent from the common people, and occupying an elevated station in society: "a narrow elite...a hierarchical social system: a system of ranked orders and classes."

The professionalization process tends to establish the group norms of conduct and qualification of members of a profession and tends also to insist that members of the profession achieve "conformity to the norm." and abide more or less strictly with the established procedures and any agreed code of conduct, which is policed by professional bodies, for "accreditation assures conformity to general expectations of the profession."