Research indicates that many general education teachers have negative attitudes about the inclusion of students with disabilities. Ways to promote positive attitudes in preservice teachers are needed, particularly in Puerto Rico, where the autism identification rate is the highest in the world. The purposes of this concurrent mixed method study were to explore the attitudes of preservice teachers toward inclusion of students with autism and to gather the perceptions of education faculty members regarding their students' attitudes. Research questions were designed to examine the attitudes of the student teachers and the reflections of faculty, to identify possible differences across preservice majors, and to gather recommendations about preparation offerings. Ajzen's attitudinal theory and Salvia and Munson's model of attitudes towards inclusion guided the study. One hundred twelve preservice teachers from a university in Puerto Rico completed the inclusion survey, and 11 preservice teachers and 8 education faculty members were interviewed. Spearman's rho and independent t-test analyses revealed significant differences in attitudes between elementary majors and both special education and preschool majors. A priori and open coding were used to identify themes related to knowledge, preparation, climate, and feelings of effectiveness. Preservice teachers' perceptions were that they were unprepared to serve students with autism; faculty members supported the need for more courses related to all special needs and especially autism. Positive social change implications include modifying preparation curricula to enhance preservice teachers' knowledge of inclusion and to support positive teacher attitudes toward the inclusion of students with autism in general education classrooms in Puerto Rico. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]