A criterion-groups validation was used to determine the classification accuracy of the Seashore Rhythm Test (SRT) and Speech Sounds Perception Test (SSPT) in detecting malingered neurocognitive dysfunction (MND) in traumatic brain injury (TBI). TBI patients were classified into the following groups: (1) Mild TBI Not-MND (n = 24); (2) Mild TBI MND (n = 27); and (3) Moderate/Severe TBI Not-MND (n = 23). A sample of 90 general clinical patients was utilized for comparison. Results showed that both SRT correct and SSPT errors differentiated malingerers from non-malingerers in the Mild TBI sample. At 96% specificity, sensitivities were 37% for SRT correct and 59% for SSPT errors. Joint classification accuracy showed that the best accuracy was achieved when using a cut-off associated with a 4% false positive error rate in the Mild TBI sample. Specificity was considerably lower in the Moderate/Severe TBI and General Clinical groups. The clinical application of these findings is discussed.