STEM teachers are in short supply due to attrition and teacher shortages. In Louisiana, over 20% of math and science classes are taught by educators who do not possess the proper certifications and over 40% of departing teachers have less than five years of teaching experience (Louisiana Department of Education, 2019). Research suggests that low teacher retention is linked to teacher dissatisfaction (Carver-Thomas and Darling-Hammond, 2017). However, teacher collaboration literature represents a conglomerate of collaborative structures and practices (Avalos-Bevan & Bascope, 2017; Vangrieken et al., 2015). This study addresses the lack of understanding concerning which forms of collaboration influences job satisfaction, work-stress, and teacher turnover intentions for early-career public middle school teachers in Louisiana. The purpose of this study was to investigate teacher collaborative practices and explore how teachers holistically perceive collaboration using an explanatory sequential mixed-methods design. The quantitative phase included 59 early-career, full-time public middle school STEM teachers, and seven participants completed the qualitative phase of the study. The results suggest no statistically significant correlations exist between teacher collaboration and job satisfaction, work-stress, and turnover intentions. The qualitative findings suggest four themes related to teachers' perspectives of collaboration. The quantitative and qualitative data were integrated using a joint display. [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.]