Socionics, in psychology and sociology, is a pseudoscientific theory of information processing and personality types. It incorporates Carl Jung's work on Psychological Types with Antoni Kępiński's theory of information metabolism. Socionics is modification of Jung's personality type theory that uses eight psychic functions instead of four. These cognitive functions are supposed to process information at varying levels of competency and interact with the corresponding function in other individuals, giving rise to predictable reactions and impressions—a theory of intertype relations. In contrast to the generally accepted views in personality psychology on age-related variability of the human psyche, socionics distinguishes 16 рsychophysiological types or types of informational metabolism unchanged throughout life. The issue of the existence of personality types is considered by modern personality psychology to be extremely controversial. However, the immutability of socionic рsychophysiological types is determined by the stability of their neural structures in the brain. At the same time, psychological personality traits can evolve and change throughout life. The special commission of the Russian Academy of Sciences (Commission on Pseudoscience) has placed socionics among such well-known pseudosciences as astrology and homeopathy.

Socionics was developed in the 1970s and 1980s, primarily by the Lithuanian researcher Aušra Augustinavičiūtė, an economist and dean of the Vilnius Pedagogical University's department of family science. The name "socionics" is derived from the word "society", because Augustinavičiūtė believed that each socionic type of informational metabolism has a distinct purpose in society, which can be described and explained by socionics.

The central idea of socionics is that information is intuitively divisible into eight categories, called information aspects or information elements, which a person's psyche processes using eight psychological functions. Each sociotype has a different correspondence between functions and information elements, which results in different ways of perceiving, processing, and producing information. This in turn results in distinct thinking patterns, values, and responses to arguments, all of which are encompassed within socionic type. Socionics' theory of intertype relations is based on the interaction of these functions between types.

Independent authors point to the insufficient empirical validity of socionics both in its basis and in its further development, as well as the practical absence of studies on socionics outside the former USSR. In the West, the term 'socionics' (German: Sozionik) is used in a different sense, to refer to an interdisciplinary area of research on distributed artificial intelligence systems and their applications to sociology.