Current research in the field of personality structure emphasizes two quite different structural representations of personality traits: the Five Factor Model (FFM) of personality traits and the Interpersonal Circumplex (IPC) model of interpersonal dispositions. There are two traditions within FFM research: (a) the lexical tradition focuses on the totality of trait-descriptive terms found within unabridged dictionaries in different languages and (b) the multivariate-trait tradition focuses on the number and nature of dimensions that have been found in research with personality questionnaires. Research from both traditions has converged on the common dimensions of Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Intellect/Openness. The NEO Personality Inventory is the most widely used and well-established questionnaire measure of these five dimensions. The IPC model focuses on dyadic relationships within an ‘interpersonal space’ in which actions and reactions are expressed as combinations of scores within the circle formed by the coordinates of Dominance and Affiliation. Different IPC models share the same circular structure but differ in their domains of application (e.g., interpersonal traits, interpersonal problems, styles of social support). The FFM and IPC models may be viewed as complementary rather than competitive, and as being applicable to different but equally important realms of knowledge.