The therapeutic working alliance between practitioner and client is a robust predictor of positive client outcomes in psychotherapy. In the current paper, we propose a social identity approach to understanding this alliance, suggesting that the alliance is best conceived of as the instantiation of shared social identification within the practitioner–client dyad. We propose that practitioners’ efforts to develop a shared social identity with clients—and, hence a successful working alliance—can be achieved through known processes of identity leadership. Here, practitioners work to develop a shared sense of “us” as the foundation for a working alliance (“identity entrepreneurship”), establish practices that recognize the importance of “us” (“identity impresarioship”), work to advance the interests of “us” (“identity advancement”), and ensure that they remain an important part of the alliance by remaining a collaborative part of this “us” (“identity prototypicality”). Evidence for the utility of identity leadership in advancing mutual collaboration with clients is reviewed, and a summary of preliminary identity leadership-based strategies to foster alliance is provided. Overall, the value of a social identity approach to the working alliance lies in its ability to (a) offer a theory-driven, testable framework for understanding and advancing the working alliance, (b) provide implementable and outcome-focused practitioner strategies, and (c) facilitate alliance across a range of demographically diverse clients. (PsycInfo Database Record (c) 2021 APA, all rights reserved)