1945–46 Tercera División

The 1945–46 Tercera División was the tenth edition of the Spanish third national tier. The competition was divided into 3 phases.

Format
The division comprised 100 clubs in 10 geographic groups. The top 3 clubs in each group (30 in total) progressed to the Second Phase. The Second Phase comprised 5 groups of 6 clubs, each club playing 10 matches. The 5 group winners progressed to the Final Phase - a group of 5 clubs, each playing 8 matches. The top two teams were promoted to the Segunda División and the third-placed team played off against the 12th placed team in the Segunda División.

Group 10 repechage

 * Replay:

Between Cadiz and Tetuán was played a match to play on this group, Cádiz promoted.
 * Calavera was withdraw of this group before the start the competition.

Promotion/relegation playoff
Note: Baracaldo were promoted to the Segunda División.