A shift toward shared practice in schools has emerged and teachers are moving from isolation to collaboration (Hindin, Morocco, Mott, & Aguilar, 2007). One of the structures that supports collaboration is the collaborative team. Teams have great potential, however, their failure can impact the organization's progress and the team members' satisfaction in working with the team (Aube & Rousseau, 2005; Peeters, Rutte, van Tuijl, & Reymen, 2006). There is increasing evidence that personality may be related to the quality of social interactions occurring in teams (Waldman, Atwater, & Davidson, 2004). This study examined the relationship between the Big Five personality traits (i.e., Extraversion, Conscientiousness, Agreeableness, Emotional Stability, and Openness to Experience) and Satisfaction with the Team. A mixed methods sequential approach utilized a survey methodology followed by open-ended interviews. A questionnaire was administered to a purposive sample of N = 244 full-time educators from N = 49 interdisciplinary teams at N = 7 middle schools in Rhode Island. It assessed the Big Five personality traits, demographic variables, general job satisfaction, and team member satisfaction. These quantitative data were analyzed using descriptive and correlational statistics as well as multiple regression. The open-ended interviews were conducted with n = 14 teachers. A synthesis of coded themes was used to investigate team members' perceptions about team members' personalities and interactions. The quantitative findings indicate no significant relationship between the BFI traits and Satisfaction with the Team. However, the relationships varied across team tenure groups. Team-level analyses indicate a significant negative correlation between Satisfaction with the Team and maximum (highest member score) Extraversion ( r = 0-.44, r[superscript 2] = 0.19, p = 0.002; medium effect size) and maximum Agreeableness ( r = -0.31, r[superscript 2] = 0.10, p = 0.031; medium effect size). The qualitative data reveal that team climate, team member personality, and team personality configuration are factors related to Satisfaction with the Team. This study extended the research on teams by investigating longer-lived work teams in real life educational settings. Recommendations for administrators and interdisciplinary team teachers regarding professional development and team selection are provided as well as recommendations for future research. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]