XP teams have the right to do their best work. On the other hand, customers have the right to specify and pay for only the quality they need. How does one reconcile two potentially conflicting points of view? Is quality negotiable? If so, how do we go about negotiating it? This paper will explore the following questions: Is quality negotiable? How can we negotiate quality? What are internal and external quality, and are either or both negotiable? What's the XP tester's quality assurance role? How far should testers go in helping the customer define acceptance criteria?