AbstractThe Working Alliance Inventory‐Short Revised (WAI‐SR) is a recently refined measure of the therapeutic alliance that assesses three key aspects of the therapeutic alliance: (a) agreement on the tasks of therapy, (b) agreement on the goals of therapy and (c) development of an affective bond. The WAI‐SR demonstrated good psychometric properties in an initial validation in psychotherapy outpatients in the USA. The generalizability of these findings is limited because in some countries a substantial portion of individual psychotherapy is delivered in inpatient settings. This study investigated and compared the psychometric properties of the WAI‐SR in German outpatients (N = 88) and inpatients (N = 243). In both samples reliability (? ? 0.80) and convergent validity with the Helping Alliance Questionnaire were good (r > 0.64). Confirmatory factor analysis showed acceptable to good model fit for the proposed Bond‐Task‐Goal model in both samples. Multi‐group analysis demonstrated that the same constructs were measured across settings. Alliance ratings of outpatients and inpatients differed regarding the overlap of alliance components and the magnitude of the alliance ratings: The differentiation of the alliance components was poorer in inpatients and they reported lower alliances. Unique aspects of the alliance in inpatient treatment are discussed and a need for further research on the alliance in inpatient settings is pointed out. Overall, the WAI‐SR can be recommended for alliance assessment in both settings. Copyright © 2009 John Wiley & Sons, Ltd.Key Practitioner Message The Working Alliance Inventory‐Short Revised (WAI‐SR) is a 12‐item measure for the assessment of the therapeutic alliance. The WAI‐SR is pantheoretic and captures three key alliance aspects: (a) agreement on the tasks of therapy, (b) agreement on the goals of therapy and (c) development of an affective bond. This study demonstrates good psychometric properties of the WAI‐SR in outpatients and inpatients. The WAI‐SR is ready to be used by psychotherapists interested in the therapeutic alliance, for supervision and process research.