Misophonia, also known as selective sound sensitivity syndrome, is a condition characterized by strong dislike of specific sounds with accompanying distressing reactions. To date, misophonia is still poorly understood. This study aimed to identify factors associated with severity of misophonic symptoms in Singaporean psychiatric patients. Ninety-two psychiatric patients were recruited from a large teaching hospital in Singapore in a cross-sectional study. Socio-demographics, severity of depression, anxiety and stress, and severity of misophonic symptoms were analyzed. Correlation analysis showed that anxiety, depression, and stress scores—as measured by the Depression, Anxiety and Stress Scales-21 (DASS-21)—were significantly positively correlated with the Amsterdam Misophonia Scale (A-MISO-S) scores. After adjustment for confounding factors, multivariate regression analysis showed that anxiety (β = 0.385, p = 0.029) remained significantly associated with A-MISO-S. Age, gender, depression, and stress were not significantly associated with the severity of misophonia. The findings showed that the severity of anxiety was associated with severity of misophonia in Singaporean psychiatric patients. Further research is needed to explore the nature of misophonia and its relationship with other psychiatric disorders.