The 2021–22 III liga season was the 14th edition of the fourth tier domestic division in the Polish football league system since its establishment in 2008 under its current title (III liga) and the 6th season under its current league division format.

[2] The league was operated by the Polish Football Association (PZPN).

The competition was contested by 73 clubs split geographically across 4 groups, with the winners of each group gaining promotion to the II liga.

The teams included semi-professional clubs (although a few are professional) and the reserve teams of professional clubs.

73 teams were divided into four groups according to geographical criteria:[2] Since 2021–22 season each group of III liga was operated by Polish Football Association (PZPN), not a different voivodship football association.