Sandbagging is common amongst athletes and our current methods of identifying it are insufficient, inconsistent, and expensive. The purpose of the current study was to determine if scores on commonly used and relatively inexpensive sideline concussion tests (e.g., Standardized Assessment of Concussion [SAC] and Standardized Concussion Assessment Tool, Fifth Edition [SCAT-5]) could differentiate between individuals asked to provide their best effort or sandbag. Identifying individuals who provide suboptimal effort at baseline is an important task because it will ultimately improve our abilities to detect true injuries and reduce negative and long-term effects associated with concussions. It was hypothesized that the Immediate Memory, Delayed Recall, Concentration, and Total Scores on each test would accurately differentiate sandbagging and best effort. Participants included 38 undergraduate college students at a Midwestern University. Participants were randomly assigned to experimental groups that were asked to sandbag or provide their best effort during their completion of a series of performance validity tests, cognitive measures, and sideline concussion tests. Results of logistic regression analyses indicated that the SAC and SCAT-5 could not differentiate between the two groups (p’s > .025). It is possible that the null results are accurate as the SAC and SCAT-5 were not designed to assess performance validity and may not be able to accurately distinguish best effort from poor effort. However, this study is the first to examine this issue using the SAC and SCAT-5, and given its limitations, results should be considered inconclusive. Future research should not only address the limitations of this study, but also keep larger considerations related to base rates, cut scores, and overall implementation of research findings in mind. In the meantime, results provide further evidence to support the use of a multidisciplinary approach for concussion assessment and treatment that involves neuropsychologists as part of the athletic care team.