Objective: Gelastic Seizures-Hypothalamic Hamartoma (GS-HH) is a rare syndrome that may go undiagnosed/misdiagnosed due to behavioral and developmental presentations that are comorbid with other disorders. Neuropsychological functioning of an 8-year-old Asian American girl with previous diagnosis of Social Anxiety and history of unrecognized GS-HH until progression to partial and absence seizures is presented. Decline in short-term memory and academic performance, learning difficulties, personality changes, temperature dysregulation, and rapid weight gain were reported within the past year. Method: Patient presented with unrecognized Gelastic seizures since infancy, and partial and absence seizures since 2012. MRI revealed HH protruding into suprasellar cistern in left paramedian, displacing left optic tract to the right, left side of optic chiasm superiorly and to the right, and minimally displacing the infundibulum to the right. Comprehensive neuropsychological testing of intellectual, memory, perceptual/spatial, executive, language, attention, academic, motor, processing speed and behavioral/emotional functioning was completed 8 months after her diagnosis. Results: Neuropsychological testing revealed average intelligence and overall average to superior academic skills with the exception of Math (average to limited proficiency). Other neurocognitive measures revealed superior to average expressive/receptive language, perceptual/spatial skills, and processing speed. Areas of significant weakness were identified on tasks of attention/executive functioning/ processing speed that involve numbers, confrontational naming, and unstructured verbal memory, which corroborates reported declines in functioning and correlates to neuroanatomical structures involved in GS-HH. Conclusion(s): Due to the strong behavioral component associated with early stages of GS-HH, as well as subtle cognitive changes, comprehensive neuropsychological testing will help avoid misdiagnosis and ensure appropriate treatment.