The 1951–52 Tercera División season was the 16th since its establishment.
Three withdrew before the end of the season.
The 6 group winners were promoted to the Segunda División.
It had been planned to reorganise the Segunda and Tercera Divisiónes but the plan was never implemented and the Promotion play-offs had no consequence.
The bottom three clubs in Groups I and II of the Segunda División were relegated and no other Tercera División clubs were promoted.