Despite pervasive evidence that general mental ability and personality are unrelated, we investigated whether general mental ability may affect the response process associated with personality measurement. Study 1 examined a large sample of job applicant responses to four personality scales for differential functioning across groups of differing general mental ability. While results indicated that personality items differentially function across highly disparate general mental ability groups, there was little evidence of differential functioning across groups with similar levels of general mental ability. Study 2 replicated these findings in a different sample, using a different measure of general mental ability. We posit that observed differences in the psychometric properties of these personality scales are likely due to the information processing capabilities of the respondents. Additionally, we describe how differential functioning analyses can be used during scale development as a method of identifying items that are not appropriate for all intended respondents. In so doing, we demonstrate procedures for examining other construct-measurement interactions in which respondents’ standings on a specific construct could influence their interpretation of and response to items assessing other constructs.