The six dimensions of the HEXACO model of personality are most commonly measured via the HEXACO Personality Inventory(-Revised) (HEXACO-PI(-R)), which comes in three versions (60, 100, and 200 items) and is available as a self- and observer report form in several languages. The present study meta-analytically investigates the psychometric properties of the HEXACO-PI(-R), relying on empirical data from 549 independent samples providing information about 316,133 individuals. In particular, we performed reliability generalization meta‐analyses to examine internal consistency, determined self–observer agreement, investigated structural properties in terms of the intercorrelations between the HEXACO dimensions, and established relations between the dimensions and demographic variables. Results show that all HEXACO-PI(-R) versions exhibit fairly high reliabilities and a high degree of self–observer agreement. With the exception of a moderate correlation between Honesty-Humility and Agreeableness, the HEXACO dimensions are only weakly correlated overall. Finally, notable gender differences (with women scoring higher) occurred on Emotionality and Honesty-Humility.