The ability to predict and explain the behavior of others based on their mental states, known as theory of mind, has long been studied from a developmental perspective. More recently, the cognitive neurosciences along with patient studies have revealed key brain regions involved in this process, including the temporo-parietal junction (TPJ) and more specifically, the right temporo-parietal junction (rTPJ). In split-brain patients, several interesting findings have emerged in regards to theory of mind processing. Research has uncovered that some patients demonstrate specific difficulties on tasks requiring moral reasoning and the detection of faux pas. In this study, we attempted to investigate theory of mind processing in a split-brain patient, seeking to help explain reasons behind these difficulties. We also attempted to utilize techniques designed to assess each hemisphere of the brain independently, to better understand the specialized role of the rTPJ in belief attribution. One split-brain patient, V.P., was tested on a battery of established theory of mind tasks as well as various cognitive assessment tasks. On cognitive tasks assessing processing speed and inhibitory processing, V.P. showed slower reaction times compare to controls, which may reflect specific deficits or may be explained by the careful, considerate approach V.P. took in completing the various tasks. On theory of mind tasks, V.P. did show slight deficits on belief-desire reasoning and attributing mental states compared to controls. Results from the lateralized theory of mind tasks showed that V.P.'s left and right hemispheres had difficulties completing the tasks, suggesting both hemispheres may be required for such demanding processing tasks. A clear explanation of the exact reasons for V.P.'s performance across these tasks and how they relate to one another will require further investigation and analysis.