This volume contains the papers accepted for presentation at the 15th Wo- ing Conference on Requirements Engineering: Foundation for Software Quality (REFSQ 2009), held in Amsterdam during June 8-9, 2009. Since 1994, when the ?rstREFSQ tookplace, requirementsengineering (RE) has never ceasedto be a dominantfactor in?uencing the quality of software, s- tems and services. Initially started as a workshop, the REFSQ working conf- ence series has now established itself as one of the leading international forums for discussing RE in its many relations to quality. It seeks reports on novel ideas and techniques that enhance the quality of RE products and processes, as well as re?ections on current research and industrial RE practices. One of the most appreciated characteristics of REFSQ is that of being a highly interactive and structured event. Each session is organized in order to provokediscussion among the presenters of papers, discussants and all the other participants.Typically, after a paper is presented, it is immediately discussed by one or two pre-assigned discussants, then subject to a free discussion involving all participants. At the end of each session, an open discussion of all the papers presented in the session takes place. REFSQ 2009 maintained this tradit