The size of the Greek VAT Gap has been consistently high throughout the last two decades in comparison with the European Union's (EU) average. In order to better understand which specific productive sectors in the Greek economy play a more significant role in VAT revenue collection, VAT evasion and in measuring and limiting the Greek VAT Gap, an attempt to quantify and analyze the Gross Value Added/Gross Domestic Product (GVA/GDP) ratio of each productive sector was made. Design/Methodology/Approach: Specifically, using the NACE Revision 2 standard used by Eurostat, the various Greek productive sectors were broken down into fifteen (15) categories and examined for a period of 21 years (between 1997 and 2018) using econometric models based on time series data. In addition, the VAT Revenue Ratio (VRR) was used as a proxy dependent variable in order to measure the Greek VAT Gap. Findings: The analysis revealed that of the fifteen (15) economic sectors examined in this paper, four (4) were found to be statistically significant in regards with the Greek VAT gap. Specifically, the Catering and Accommodation services sector (I), the Public Administration sector (O) and the Agriculture sector (A), had a positive relationship, with the increase of their share in GDP being associated with an increase in the VAT gap. On the other hand, the Industrial sector's (B, D, E) share of GDP is associated with a reduction in the VAT gap. Practical Implications/Originality/Value: The results of this paper can shed light into the complexity of identifying the economic activities that influence the Greek VAT Gap, as well as produce more sector-specific countermeasures for limiting VAT non-compliance and evasion.