The purpose of this study is to examine the moderating effect of non-audit services fees on the relationship between size, profitability, leverage, capital intensity, inventory intensity, financial distress and ethnicity with aggressive tax planning. This study uses a sample from companies listed on the Malaysian (Access, Certainty, Efficiency (ACE) Market from 2014 to 2018, comprising of 105 firm year-observations. The finding shows that the non-audit services fee moderate the relationship between size, profitability, leverage, inventory intensity, financial distress and ethnicity with aggressive tax planning except for capital intensity. It is hoped that the finding can assist readers in understanding the nature of companies listed on the ACE Market, particularly their behaviour towards tax planning. This study contributes to knowledge in the areas of financial accounting and taxation specifically on aggressive tax planning, by introducing the moderating variable of non-audit services fee. The uniqueness of the use of companies listed on the Malaysian ACE market will provide new avenue on the discussion on an aggressive tax planning issue, which usually more focus on big firms. The framework used in the present study could serve as a basis for research in other developing countries or regions.