The Salamanca Accord advocating the implementation of inclusive education for learners with special needs was signed in 1994, as well as the Convention of the Right of Person's with Disabilities in 2006. Yet, Sierra Leone faces challenges to implement fully inclusive education in schools. The purpose of this mixed-method study was to examine teachers' attitudes towards inclusion in mainstream classrooms. The conceptual framework for this study was premised on Azden's theory of planned-behavior, which maintains that attitude and behaviors are products of experiences acquired. Using a Spearman rho correlations and descriptive statistics to analyze the data, gender, age, educational background, and teaching experience were examined to determine if they had any significant relationship with attitudes of teachers towards inclusion in Sierra Leone. In this mixed-method study, 100 primary and secondary teachers in Sierra Leone completed the Attitudes toward Inclusion in Africa Scale, and 10 teachers took part in a one-on-one interview. The results showed no significant relationship between the independent variables (gender, age, educational background, and teaching experience) and the dependent variables (attitudes towards inclusion). Despite the absence of a statistically significant relationship, the participants' interview data analyzed using Nvivo revealed an in-depth understanding of the negative attitude of teachers toward inclusive education in Sierra Leone. Findings may encourage positive social change by providing information that may be used by the Ministry of Education to develop a comprehensive inclusion model with the help of teachers. This study could be used to help create a platform for teachers' training that will ensure a positive attitude towards inclusive education in the country.