This paper addresses the growing VAT gap issue in European countries from 2011 to 2020. It aims to determine whether the implementation of SAF-T reporting has resulted in a reduction of the VAT gap. For this purpose, the Difference-in-Differences method, with multiple periods, was employed in the study. Additionally, the panel study conducted later in the paper identifies the factors influencing the VAT gap. The results show that introducing SAF-T in Portugal, Lithuania, and Poland helped to reduce this gap. Furthermore, countries with higher ICT tax administration expenditures, a higher ratio of domestic turnover to intra-community supply of goods, where the SAF-T solution is implemented, have a lower VAT gap.