Electronic filing system (e-filling) is a recent phenomenon in Tanzania. The Tanzanian Government, through its revenue authority, TRA, in the year 2020 introduced a tax e-filling system for the effective collection of various types of taxes. Since the inception of the tax e-filling system in Tanzania, only a few studies have focused on retailers' perceptions of using such a system. This study adopted a descriptive survey design conducted in Tanzanian cities using a set of closed-ended questionnaires to a random sample of 423 taxpayers. The main finding of the study showed that perceived usefulness and user satisfaction significantly influence users' adoption intention of e-filling ([β = 0.396, p < 0.000; β = 0.343, p < 0.000, respectively]). Additionally, the study indicated a broad discrepancy between the advantages of tax e-filling to taxpayers, hence downplaying its usage/adaptability. The study recommended that awareness-raising campaigns and training be initiated to understand the tax e-filling system better. Policy-wise, the study contributes to the Income Tax Act, Cap. 332 R.E., 2019, the Tanzania Development Vision 2025, and the National Strategy for Growth and Reduction of Poverty I & II.