Kelley (1921-2003): was a social psychologist, focusing on interpersonal relationships and contributing to attribution theory - how individuals 'attribute' causes to events, for instance a "situational" or "dispositional" factor.

kin altruism: in evolutionary psychology, the concept that individuals help those who are close relatives, because it fosters the transmission of their genes.

kinaesthetics: a term used to describe the response and feedback from movement sensations in the muscles or joints.

kinship (family) studies: research that examines correlations of traits or behaviours between individuals who share differing degrees of genetic similarity.

Klinefelter's syndrome: see XXV syndrome.

knowledge: the psychological result of perception and learning and reasoning.

Kobasa: (1979): examined resistance to stress, in particular “hardiness” to stress, characterised by commitment, control and challenge.

Korsakoff's syndrome: a type of amnesiacommonly found in chronic alcoholics, caused by a lack of Vitamin D (thiamine).