The use of unproctored internet-based testing for employee selection is widespread. Although this mode of testing has advantages over onsite testing, researchers and practitioners continue to be concerned about potential malfeasance (e.g., cheating and response distortion) under high-stakes conditions. Therefore, the primary objective of the present study was to investigate potential malfeasance effects on the scores of an unproctored internet-based cognitive ability, and a personality test. This was accomplished by implementing a within-subjects design in which test takers first completed the tests as job applicants (high-stakes) or incumbents (low-stakes) then as research participants (low-stakes). The pattern of cognitive ability test score differences was more consonant with a psychometric practice effect than a malfeasance explanation. Thus, the results suggest that, if present, there was no evidence to indicate that wide- scale or systematic malfeasance unduly affected the test scores. This may have been due to the speeded nature of the test, which was used to preempt the potential for widespread cheating. Additionally, the unproctored personality administration resulted in similar mean shifts and similar proportions of test takers being suspected of distorting their responses as that reported in the extant literature for proctored tests. In their totality, these results suggest that an unproctored internet-based administration does not uniquely threaten personality measures in terms of elevated levels of response distortion compared to proctored measures.