As an important issue in the fiscal structure of a country, tax gap is defined as the difference between tax burden that the taxpayer should face and the amount actually paid. In this study, tax gap was evaluated by the framework of the Value Added Tax. The reason behind this choice, i.e. Value Added Tax Gap (VAT Gap) is to make an effort to evaluate the efficiency of the tax administration, the compliance of the tax payers and the relationship between policy gap and the compliance gap. With this aim, VAT Gap and the various methods to calculate this gap were examined. Furthermore, based on the reports by the European Commision, VAT Gap in Turkey for 1993-2014 period were estimated and evaluated by employing topdown method.