This article presents a psychometric study of the short form of the Social and Emotional Loneliness Scale for Adults (SELSA-S). Data were collected via self-report measures and mail surveys from several samples including university students, spouses of military personnel, and psychiatric patients. A total of 1,526 individuals took part in this study. Results indicated that the scores from the three scales of the SELSA-S were highly internally reliable. Concurrent validity for the scales was indicated by the statistically significant relationships with other measures of loneliness. Construct (convergent and discriminant) validity was supported by strong relationships with measures of the adequacy of intimate relationships (e.g., attachment and social intimacy) and by the association of the three types of loneliness to measures of social competence, self-esteem, trust, health, and well-being. Finally, results from a factor analysis indicated that the three-factor model of the SELSA-S provided the best fit to the data.