Objective: To investigate sex differences, as well as the influence of sex upon questionable validity scores (“sandbagging”) on baseline neurocognitive testing among college athletes. Method: A chi-square analysis was conducted to examine the relation between sex and baseline neurocognitive test scores that were below the suggested validity cutoffs. Subjects included 680 male and 293 female college athletes at an NCAA Division III university who received baseline testing as part of their university’s concussion management program. The Immediate Postconcussion Assessment and Cognitive Testing neurocognitive battery (ImPACT) was used, and baseline testing was administered during an athlete’s pre-season. Results: The relation between sex and “sandbagging” scores on the Verbal Memory Composite was significant, x 2 (1, N ¼ 973) ¼ 7.850, p ¼ .005. Specifically, on average, men scored below validity cutoffs more frequently than women (12 vs. 5%). The relation between gender and Visual Memory Composite “sandbagging” scores was not significant, x 2 (1, N ¼ 973) ¼ 0.461, p ¼ .497. Conclusion: A significant relationship exists between sex and questionably valid performance on neurocognitive baseline testing, with men being more likely to “sandbag” than women.