We used exploratory structural equation modeling to examine gender-based measurement invariance (MI) in the HEXACO-100 across three samples that varied in terms of age (undergraduate students in Study 1, working adults in Studies 2 and 3) and testing context (research context in Studies 1 and 2, high-stakes selection context in Study 3). Across three studies, we consistently found support for configural and metric invariance but not scalar invariance. However, the effect size measures of non-invariance were generally small. That said, in the Emotionality scale, for the same latent score, females scored higher than males due to measurement non-invariance (between 0.26 and 0.48 standard deviation units). Thus, the observed mean gender differences overestimated the true mean gender differences. The current study provides detailed evidence regarding gender-based MI of HEXACO personality scales. More generally, it provides insight regarding the effect that measurement artifacts can have on understanding psychological gender differences at the latent level.