This paper endeavours to offer a detailed understanding regarding three main philosophical positions including Ontology, Epistemology and Methodology and how various assumptions behind each of them can be addressed in a mixed methods study. First, it elaborates on the questions such as, what is meant by ontology? What ontological positions have usually been adopted by the researchers? How can an ontological position be taken in a mixed methods study? Later, the study discusses how the questions regarding epistemology, the choice regarding epistemological positions and the questions regarding epistemology may be addressed in a mixed methods study. Finally, this paper offers a comprehensive explanation of methodology, the qualitative and quantitative approaches and the benefits of mixing both the methods in a single study. It is hoped that this paper will help researchers to enrich their understanding regarding philosophical underpinnings that will help them to carry out their own research.