|Founded||7 January 2007|
|Number of teams||337 (in 2019/20)|
|Level on pyramid||5|
|Promotion to||III liga|
|Relegation to||Liga okręgowa or V liga|
|Domestic cup(s)||Polish Cup|
|Current: 2021–22 IV liga|
IV liga (Czwarta Liga) is the fifth level of the Polish football league system. The current structure of IV liga was created in season 2000/01 after introducing new administrative division of Poland. 16 clubs, one from each voivodeship (province), are promoted to III liga. The bottom clubs are relegated to Liga okręgowa or V liga (depending on the voivodeship).
Until the end of the 2007/08 season IV liga lay at fourth tier of league system but this was changed with the formation of the Ekstraklasa as the highest level of football league in Poland.
In 2019/20 season, there are 20 parallel groups of IV liga. There are two groups in 4 voivodeships but only one club can be promoted after winning the play-offs between the winners of these two groups.