The US Catholic school system is the largest non-public school system. Teachers in US Catholic schools support students with diverse learning needs in significant numbers without the legal and policy support and funding found in the public school system. In placing a Catholic school general education teacher in the role of primary inclusive support, the question of their attitudes, concerns, and efficacy on inclusion became the focus of this research. Using quantitative surveys, including open-ended questions, allowed for the collection of qualitative and quantitative data. Utilizing the Theory of Planned Behavior (Ajzen, 1991) and the Factors found to influence teacher self-efficacy for inclusive education, Wray et al. (2022) to view teachers' responses and experiences as a gauge of their intentions to teach inclusively. This study recruited elementary teachers from one Midwest Catholic Archdiocese to participate in an electronic survey. The survey responses identified some generalities within the population. Two areas with overall positive response rates were teacher beliefs that all students should be included and the academic and social benefits of inclusion for students with diverse learning needs. Two areas of concern included teachers' generally high levels of concern related to their knowledge and skill needed to teach diverse learners and that diverse learner inclusion will cause them to have increased stress and anxiety levels. Additionally, when viewing the data on efficacy, numerous respondents identified low confidence levels related to teaching students with disabilities in their general education classroom. Due to limitations, including low response rates, data analysis yielding generalizable results was limited. However, exploratory analysis did identify teachers' common beliefs, concerns, attitudes, and issues related to self-efficacy to support students with diverse learning needs. Those themes within the data present opportunities to be explored with further research. Teacher attitudes related to including students with diverse learning needs in Catholic elementary schools is an area with limited research available. This study begins to help fill the gap in Catholic school research while identifying opportunities to expand the understanding of the attitudes, concerns, and efficacy related to diverse learner inclusion of the teachers in Catholic elementary schools. [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.]