The aim of the study is to identify factors determining tax gaps in Poland. The following taxes are analyzed: value added tax (VAT), corporate income tax (CIT), personal income tax (PIT) and excise tax. It is assumed that there are common factors determining tax gap for taxes: VAT, CIT, PIT and excise duty in Poland. On the basis of econometric panel models for the EU or OECD countries presented in the literature, general factors determining tax gaps are identified. Then they are subjected to a detailed analysis based on the available statistical data and in‑depth literature studies for each analyzed tax. The study follows a broad approach and also discusses the tax policy gaps. Based on the analysis, the adopted hypothesis can be positivel...