Honesty-Humility, one of the six major personality dimensions included in the HEXACO model of personality structure, has previously been found to show negative correlations with workplace deviance. In this study, we hypothesised that Extraversion would moderate the relationship between Honesty-Humility and workplace deviance. In particular, we posited that the relation between Honesty-Humility and workplace deviance would be stronger among employees who are high on Extraversion than among those low on Extraversion. The hypothesis was tested using three different samples across Australia, Canada, and the Netherlands. It was found in two of the three samples that high levels of Extraversion did indeed amplify the relationship between (low) Honesty-Humility and workplace deviance. Results suggest a potentially important role for multiplicative effects of personality variables on workplace criteria. © 2011 The Authors. Applied Psychology: An International Review © 2011 International Association of Applied Psychology.