This paper introduces the Alliance Approach, a participatory approach to problem solving and goal attainment through agency-enhancing behavioral change. The Alliance Approach is grounded in the working alliance at work in psychology as well as cognitive and behavioral sciences between the therapist and the patient. We aim to extend the working alliance to the social sciences. We believe that extending the working alliance to a broader Alliance Approach offers new insights for agent-centered development strategies. In this paper, we focus on explaining how the Alliance Approach can enhance agency. We argue that the Alliance Approach facilitates agent-centered development that strives to promote the agency of each person involved in the development process. We follow Amartya Sen in recognizing an agent as 'someone who acts and brings about change, and whose achievements can be judged in terms of her own values and objectives, whether or not we assess them in terms of some external criteria as well' [Sen, A. 1999. Development as Freedom]. Thus, within a development context, an agent is recognized as the protagonist who makes choices that impact the world and is never merely a passive recipient of aid.