This paper explores the “triangulation approach” in social science research methods. Triangulation is an emerging method specifically in qualitative and multi-method studies. Researchers in the social sciences have increased their use of the triangulation approach recently due to the merits of this approach, especially to conduct in-depth studies through multiple inquiries. Simultaneously, this method has criticism and misconceptions among social researchers in terms of what it is, how it can be used, and the credibility of the findings when used. Therefore, (...) this paper analyses in depth what triangulation is, the types of triangulations and how they can be applied in the social sciences. The study basically adopted systematic literature review and used 30 articles published in scientific journals. The paper critically reviewed journal articles related to triangulation, revealed how different types of triangulation methods have been applied in the social sciences and highlighted the merits and cautions of applying this method. The paper theoretically contributes to understanding the phenomenon of the triangulation approach and how it connects with qualitative and multi-method studies. In addition, it revealed that the following data collection techniques from multiple sources can be exploited: in-depth interviews, focus group discussions, literature, documents, and surveys on the triangulation method to improve the credibility and reliability of the research. Furthermore, the study empirically contributes to social science researchers applying this approach with proper understanding. (shrink)