The purpose of this study was to examine the role critical reflection should play in preparing Lay leaders to serve as mission leaders in an interdisciplinary ministry. The aim of this study was to design an evidence-based case of the need for critical reflection as a tool for mission leader formation. A qualitative case study was the method in which data was collected and a case study was used because it provided a broad, all-inclusive description and analysis of the experiences of mission leaders. The case study was focused on mission leaders from senior living and healthcare, education, and social service ministries and focused on how mission leaders value critical reflection as part of their mission leader formation/development. The overarching research question that informed this study was "What role should critical reflection play in preparing lay leaders for the role of a mission leader in interdisciplinary ministry?" Through the analysis and synthesis of the interviews the question was answered. Critical reflection should play a critical role, and should continue to play a critical role in the formation of mission leaders so that they are more confident and better prepared for the task of leading a critical reflection exercise. This dissertation in practice has helped in showing what is needed from a mission leader when they are not fully prepared, academically or professionally for the position and do take on the role later in life or as a second career. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]