Clinical psychological practice is founded upon the therapeutic relationship. A science-informed practice then requires that the elements used to build that relationship have an evidence base. Thus, the chapter reviews the empirical foundations of the therapeutic relationship and what steps can be taken to build a therapeutic alliance that correlates positively with beneficial treatment outcomes. The chapter outlines in practical steps how strong therapeutic relationships can be built by evidence-based practices that strengthen the alliance in an empathic manner. It illustrates key skills of building empathy through encouraging, re-stating, and paraphrasing communications in a manner that conveys to the patient an understanding of the content and the emotion behind what is communicated. The chapter concludes with a discussion of problems that can arise in the therapeutic relationship and practical steps to manage alliance ruptures.