Grief rumination is characterized by recurring, repetitive, self-focused thoughts about the causes and consequences of loss and loss-related emotions. This cognitive process is a transdiagnostic risk factor for mental disorders, such as prolonged grief. The aim of this study was to analyze the psychometric properties of the Portuguese version of the Utrecht Grief Rumination Scale (UGRS). The sample consists of 242 bereaved adult participants with Portuguese nationality. Confirmatory Factor Analysis showed that the hierarchical model showed a better fit to the data. Average Variance Extracted was also calculated to measure convergent and divergent validity. Test-criterion validity was investigated by analyzing associations between grief rumination and measures of posttraumatic stress, prolonged grief, anxiety, and depression. Using McDonald's Omega and Cronbach's Alpha, all subscales showed adequate reliability. The UGRS showed acceptable psychometric properties, standing out as a valid instrument for practice and research in psychology in the area of bereavement.