User requirements playa central role in software development processes by bridging the needs of the business to those of the software. In many cases stakeholders need to collaborate to clarify, capture and uncover user requirements in an efficient and effective manner. However, facilitating a group of stakeholders who have got different needs and perspectives is a challenge. Many industry experts have admitted that defining user requirements is the most difficult task of software development. The overall aim of the thesis is to investigate stakeholders' collaboration in facilitated user requirements elicitation workshops and to address the challenges in this field. The research investigates a pattern approach to firstly develop a step-by-step collaborative process that can be used by practitioners in facilitated user requirements elicitation workshops. Secondly, since delivering effective facilitated workshops, especially for novice facilitators is a complex task to achieve, developing a framework that can be used to evaluate the delivery of facilitation services is suggested. This thesis investigates how patterns approach can be applied to requirements elicitation workshops in particular drawing on the field of Collaboration Engineering (CE) that describes patterns of collaboration and the design of collaborative processes. This research follows the Design Science Research (DSR) Methodology. DSR Method defines iterations within a structure that consists of five different research steps: awareness of the problem in the field of the research, suggestions as solutions to the research problem, artefact development, artefact evaluation, and conclusion of research outcomes. DSR is used in the research in two distinctive cases forming two iterative research cycles. As a result of using the method, two artefacts are developed and evaluated in this research. The main outcomes of the research are artefact one, a pattern language designed to be used in facilitated collaborative user requirements elicitation workshops and artefact two, an assessment framework for evaluating the facilitator's performance in the workshops.