Tercera Federación, previously known as Tercera RFEF, is the fifth tier of the Spanish football league system. It is below the La Liga, Segunda División, and its fellow semi-professional divisions Primera Federación and Segunda Federación.^[1] It was founded in 1929 as the third tier, and dropped down to the fourth and fifth tiers in 1977 and 2021, respectively.

On 6 May 2020, the RFEF announced the creation of a new, two-group, 40-team third division called Primera División RFEF, which made the former third and fourth divisions, Segunda División B and Tercera División, respectively, to drop down a level and change into Segunda División RFEF and Tercera División RFEF; the changes were made effective for the 2021–22 campaign.^[2][3]

In July 2022, the division was renamed Tercera Federación.^[4]

The Tercera Federación features 18 regional groups (like the former fourth tier Tercera División), corresponding to the autonomous communities of Spain (due to its size, Andalusia is divided into two groups, East and West; Ceuta is allocated to West Andalusia, while Melilla is allocated to the East), where each group is administered by a regional football federation. At the end of the season the first four teams in each group qualify for promotion play-offs to decide which teams are promoted to Segunda Federación. At least the three teams finishing bottom of each group may be relegated to the Divisiones Regionales de Fútbol. However the number of teams relegated can vary. The eighteen group champions also qualify for the following season's Copa del Rey. However reserve teams are ineligible. Along with teams from Segunda Federación, the remaining teams from the division compete in the Copa Federación.

The member clubs of the Tercera Federación for the 2023–24 season are listed below.

All group champions are promoted to Segunda Federación. Administrative promotions not included in this table.