The research was conducted to look into learner diversity in inclusive classrooms focusing on language of instruction, gender and disability issues, and their implications for education practices. A qualitative research approach was used to obtain data addressing the research problem from two inclusive secondary schools in Dar es Salaam region, Tanzania. A purposive sampling was used to obtain the schools, and research participants who were teachers and students. Open ended interviews, classroom observations, and focus group discussions were used in data collection. The findings have indicated challenges facing teachers in teaching mixed classes as well as students in such classes; especially those with disability. However, interactions between girls and boys were generally positive although the latter dominated in some classroom conversations. It is recommended that all teachers should be trained on how to handle students with special needs in particular and acquainted with general knowledge of learner diversity during initial-teacher training, and further enhanced through continued in-service trainings. Lastly, it is recommended that another study, using both quantitative and qualitative approaches, be conducted using a bigger sample involving other types of participants with special needs; and that parents of children in special needs should participate in the proposed study.