Objectives: Whiplash-associated disorders (WAD) are common and involve both physical and psychological impairments. Research has shown that persistent posttraumatic stress symptoms are associated with poorer functional recovery and physical therapy outcomes. Trauma-focused cognitive-behavioral therapy (TF-CBT) has shown moderate effectiveness in chronic pain samples. However, to date, there have been no clinical trials within WAD. Thus, this study will report on the effectiveness of TF-CBT in individuals meeting the criteria for current chronic WAD and posttraumatic stress disorder (PTSD). Method: Twenty-six participants were randomly assigned to either TF-CBT or a waitlist control, and treatment effects were evaluated at posttreatment and 6-month follow-up using a structured clinical interview, self-report questionnaires, and measures of physiological arousal and sensory pain thresholds. Results: Clinically significant reductions in PTSD symptoms were found in the TF-CBT group compared with the waitlist at postassessment, with further gains noted at the follow-up. The treatment of PTSD was also associated with clinically significant improvements in neck disability, physical, emotional, and social functioning and physiological reactivity to trauma cues, whereas limited changes were found in sensory pain thresholds. Discussion: This study provides support for the effectiveness of TF-CBT to target PTSD symptoms within chronic WAD. The finding that treatment of PTSD resulted in improvements in neck disability and quality of life and changes in cold pain thresholds highlights the complex and interrelating mechanisms that underlie both WAD and PTSD. Clinical implications of the findings and future research directions are discussed.