One of the characteristics of qualitative research is clarifying ambiguity and discovering various realities, so the data collection method is often through unstructured interviews, in-depth interviews, and direct observation of people, places, and phenomena. This condition ensures that qualitative research always asks questions about providing the data's reliability and validity. Triangulation is an approach to increase the depth of data collected, reduce bias, and increase validity and credibility. Triangulation uses multiple techniques, including the triangulation of data sources, methods, investigators, and theories. A literature review is conducted to investigate triangulation in various research disciplines. The different forms of triangulation and their applications are then thoroughly examined. In particular, doctorate students should gain a grasp of triangulation procedures in qualitative research from this work. Therefore, this study offers valuable insights for researchers who wish to enhance their research's validity, transferability, confirmability, and dependability.