2021–22 Segunda División RFEF

The 2021–22 Segunda División RFEF season was the first for the Segunda División RFEF, the new fourth highest level in the Spanish football league system. It supplanted Tercera División, which downgraded to the fifth tier as Tercera División RFEF and succeeded the old Segunda División B, which was replaced by Primera División RFEF as the third level of the pyramid. Ninety teams will participate, divided into five groups of eighteen clubs each based on geographical proximity. In each group, the champions automatically promoted to Primera División RFEF, and the second to fifth placers will play promotion play-offs. The last five teams in each group will be relegated to the Tercera División RFEF; in addition, the four worst teams classified 13th in their group will play play-offs to define the last two relegation places.