The purpose of this study was to explore the perceived self-efficacy and attitudes of primary school teachers towards the inclusion of pupils with disabilities, and to identify all factors that may contribute to influence teachers' perceived self-efficacy and attitudes. About ten background variables were studied in relation to teachers' self-efficacy and attitudes in teaching pupils with disabilities. It is a correlational study design and it was carried out through a survey questionnaire that involved 119 primary school teachers from Songea district, Tanzania. The findings of the ANOVA tests concludes that teachers' training level in special needs education, number of pupils with disabilities per classroom, size of the class, and the type of disability experienced by pupils are the factors which may affect teachers' self-efficacy and teachers' attitudes towards teaching pupils with disabilities. However, the results of multiple regression analyses showed that only teachers training in special needs education moderately predicted teachers' perceived self-efficacy, while the type of disability experienced by pupils in the classroom predicted teachers' attitude with a small strength