Professionalization is a social process by which any trade or occupation transforms itself into a true "profession of the highest integrity and competence." The definition of what constitutes a profession is often contested. Professionalization tends to result in establishing acceptable qualifications, one or more professional associations to recommend best practice and to oversee the conduct of members of the profession, and some degree of demarcation of the qualified from unqualified amateurs (that is, professional certification). It is also likely to create "occupational closure", closing the profession to entry from outsiders, amateurs and the unqualified.

Occupations not fully professionalized are sometimes called semiprofessions. Critique of professionalization views overzealous versions driven by perverse incentives (essentially, a modern analogue of the negative aspects of guilds) as a form of credentialism.