As caseloads for special education teachers continue to rise and as more students with disabilities enter the regular education setting (U.S. Department of Education, 2016), the need for co-teaching, in which a special education teacher and regular education teacher work together in one classroom to meet all students' needs, is significant. Co-teaching can take several forms, and researchers have observed that the model of co-teaching utilized often varies between classrooms and even within co-teachers over time (Friend, 2011). This study sought to gain a better understanding of the decision-making process and experiences of elementary school (K-6) teachers working in co-teaching classrooms when implementing the six co-teaching models as defined by Friend and Cook (2008). There are six commonly used co-teaching models that the special education teacher and regular education teacher can implement in the practice of co-teaching throughout the day, and these models have been thoroughly explored over the years. However, there was scarce research on the teachers' decision-making process as to how, when, and why they choose to utilize each of the models throughout their day and their experiences with using the six models in the classroom. This study sought to better understand the decision-making process and experiences of co-teachers utilizing some or all of the six co-teaching models, and aimed to answer these two important questions: "What were the experiences of New Jersey public school elementary co-teachers (K-6) with utilizing the six co-teaching models while working in co-teaching classrooms? How do New Jersey public school elementary co-teachers (K-6) decide which of the six co-teaching models to use while working in co-teaching classrooms?". [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.]