Psychological Types (German: Psychologische Typen) is a book by Carl Jung that was originally published in German by Rascher Verlag in 1921, and translated into English in 1923, becoming volume 6 of The Collected Works of C. G. Jung. It is the baseline of many personality typology systems, particularly Myers Briggs.

In the book, Jung proposes four main functions of consciousness: two perceiving or non-rational functions (Sensation and Intuition), and two judging or rational functions (Thinking and Feeling). These functions are modified by two main attitude types: extraversion and introversion.

Jung proposes that the dominant function, along with the dominant attitude, characterizes consciousness, while its opposite is repressed and characterizes the unconscious. Based on this, the eight outstanding psychological types are: Extraverted sensation / Introverted sensation; Extraverted intuition / Introverted intuition; Extraverted thinking / Introverted thinking; and Extraverted feeling / Introverted feeling. Jung, as such, describes in detail the effects of tensions between the complexes associated with the dominant and inferior differentiating functions in highly and even extremely one-sided types.

Extensive detailed abstracts of each chapter are available online.

Jung's interest in typology grew from his desire to reconcile the theories of Sigmund Freud and Alfred Adler, and to define how his own perspective differed from theirs. Jung wrote, "In attempting to answer this question, I came across the problem of types; for it is one's psychological type which from the outset determines and limits a person's judgment." He concluded that Freud's theory was extraverted and Adler's introverted. Jung became convinced that acrimony between the Adlerian and Freudian camps was due to this unrecognized existence of different fundamental psychological attitudes, which led Jung "to conceive the two controversial theories of neurosis as manifestations of a type-antagonism."

The characteristic animosity between the adherents of the two standpoints arises from the fact that either standpoint necessarily involves a devaluation and disparagement of the other. So long as the radical difference between [Adler's] ego-psychology and [Freud's] psychology of instinct is not recognized, either side must naturally hold its respective theory to be universally valid.

Due to the multifarious nature of fantasy, the fantasies of both Adlerian and Freudian patients contained ample empirical evidence to reinforce the steadfast belief of each side in their respective theories.

The scientific tendency in both is to reduce everything to their own principle, from which their deductions in turn proceed. In the case of fantasies this operation is particularly easy to accomplish because...they...express purely instinctive as well as pure ego-tendencies. Anyone who adopts the standpoint of instinct will have no difficulty in discovering in them the "wish-fulfillment," the "infantile wish," the "repressed sexuality." And the man who adopts the standpoint of the ego can just as easily discover those elementary aims concerned with the security and differentiation of the ego, since fantasies are mediating products between the ego and the instincts. Accordingly they contain elements of both sides. Interpretation from either side is always somewhat forced and arbitrary, because one side is always suppressed.