The main objective of the study was to determine whether there exists a relationship between collaborative team teaching and teachers’ effectiveness in an inclusive context in public primary schools in South West Region of Cameroon. The descriptive correlation design was used for the study and the sample was drawn using multi-stage sampling, purposive and simple random techniques. The sample consists of 248 respondents comprising 4 Regional Pedagogic Inspectors of Basic Education (RPIs), 40 teacher trainers from Government Teacher Training Colleges (GTTCs), 40 head teachers and 168 teachers of public primary schools in Meme and Fako Divisions of South West Region. The instruments used were four scale Likert questionnaire and an interview guide. Quantitative data were analyzed using Statistical Package for Social Science (SPSS) Version 12. Furthermore, descriptive statistics were used to analyze data to answer questions while the Spearman’s two tailed correlation was used to test the hypothesis. The qualitative data were analyzed using themes drawn for thematic analysis of open-ended questions and structural interview guide. This study revealed that there is a positive significant relationship between Collaborative Team Teaching and teachers’ effectiveness in an inclusive context in public primary schools in Fako and Meme divisions in South West Region of Cameroon (ɼxy-cal = .330**) greater than the critical value (ɼxy-crit = .113) at 0.05 level of significance. Based on this finding it was recommended that school administrators should ensure that teachers should practice collaborative team teaching in order to be effectiveness in an inclusive context.