Self-determination plays a vital role in the educational journey of students with a dis/ability. However, opportunities to cultivate self-determining skills for elementary students with dis/abilities in an inclusive co-taught classroom are limited. This can be attributed to the intersectionality of ableism and ageism, two oppressive societal constructs that elementary co-teachers may consciously or subconsciously hold. Since the inception of educating students with dis/abilities in their least restrictive environments, co-teaching classrooms have been deemed as the most appropriate setting for many students considering the continuum of special education services. The purpose of this study was to examine how elementary co-teaching teams perceive the experiences and capabilities of students with dis/abilities in their classroom. A qualitative, hermeneutic phenomenology of practice approach was used for this research. The study used self-determination theory and critical disability theory frameworks. Data included individual semi-structured interview, a co-taught lesson plan artifact, and a semi-structured interview with a co-teaching team. An inductive, qualitative thematic analysis produced four themes. The themes were that educators' mindsets toward co-teaching impacted perceptions of students with dis/abilities, inclusion considerations for students with dis/abilities were (subconsciously) ableist, self-determination development and acquisition were contingent on student age, and Universal Design for Learning (UDL) was an underutilized framework for instruction. Implementing co-teaching approaches that embody the utilization of UDL strategies can provide optimal, inclusive educational experiences for students with dis/abilities that prioritize the development of self-determination skills. Limitations and recommendations for future research are provided. [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.]