A strategy is a tactical plan to achieve a goal under a condition of a predetermined process. It also denotes a system of developing, formulating and finding a process that could ensure a lasting solution when successfully implemented. The objective of this study is to understand the strategy needed for internal audit function in tax administration. In order to achieve this, a case study methodology was used on Federal Inland Revenue Service Nigeria (FIRS). Qualitative research paradigm was used to collect data from nine internal auditors using the face-to-face interview method. The collected data were analysed using Nvivo10 qualitative software for thematic analysis. Findings of the study show that strategies of internal auditing in tax administration include ensuring adequate human resource that could perform the audit function skillfully, and comprehensive audit work plan to guide the auditing process. In addition, selecting a suitable approach to actualize the audit work plan is also a crucial auditing strategy. The study recommends that FIRS shall provide all the material and human resources needed to support the internal audit strategy development for effective function of auditing. This, in turn, could assist internal audit activities in improving tax administration performance.
