BACKGROUND: Schizophrenia (SZ) is a psychiatric disorder that often involves reduced social functioning. Frontal alpha asymmetry (FAA) is a neurophysiological marker extracted from electroencephalogram (EEG) data that is likely related to motivational and emotional tendencies, such as reduced motivation across various psychiatric disorders, including SZ. Therefore, it may offer a neurophysiological marker for social functioning. OBJECTIVES: The present study aimed to examine whether FAA is related to social functioning in schizophrenia. Additionally, a group of people with autism spectrum disorder (ASD) was included to explore whether findings are unique to schizophrenia, or whether they are found in another diagnostic group with atypical social behaviors. METHODS: Analysis of variance and regression models were used to evaluate data from resting-state EEG, clinical interviews, and self-report measures. Data from 33 participants with SZ were compared to 38 healthy controls and 30 individuals with ASD. RESULTS: Although people with SZ showed differences in FAA compared to healthy controls, the altered neurophysiology was not related to reduced social functioning in SZ. However, FAA was related to social functioning in people without a psychiatric diagnosis. Additionally, comparisons between the SZ and ASD group revealed few differences in patterns of FAA and social functioning, suggesting commonalities between the disorders in these areas. CONCLUSIONS: FAA likely does not present a neurophysiological marker for reduced social functioning in schizophrenia, though future work should examine its role in other possible clinical manifestations shared between schizophrenia and ASD.