The 1947–48 Tercera División was the 12th edition of the Spanish national third tier.
8 geographic groups of 14 clubs (112 in total) participated. The 8 group champions qualified for the Fase Intermedia which comprised 2 groups of four clubs playing a round robin. The group winners and runners up qualified for the Fase_Final which was another round robin with the top two clubs earning promotion to Segunda División.
Note: Manchego were reprieved following the resignation of other clubs.
Note: Numancia and Dep. Alavés were reprieved following the resignation of other teams.
Note: Conquense were reprieved following the resignation of other teams.