The 2013 Segunda División B play-offs (Playoffs de Ascenso or Promoción de Ascenso) were the final playoffs for promotion from 2012–13 Segunda División B to the 2013–14 Segunda División. The four first placed teams in each of the four Segunda División B groups played the Playoffs de Ascenso and the four last placed teams in Segunda División were relegated to Segunda División B. It also decided the three teams which placed 16th to be relegated to the 2013–14 Tercera División.
The four group winners have the opportunity to promote directly and become the overall Segunda División B champion. The four group winners will be drawn into a two-legged series where the two winners will be promoted to the Segunda División and will enter into the final for the Segunda División B champion. The two losing semifinalists will enter the playoff round for the last two promotion spots.
The four group runners-up will be drawn against one of the three fourth-placed teams outside their group while the four third-placed teams will be drawn against each other in a two-legged series. The six winners will advance with the two losing semifinalists to determine the four teams that will enter the last two-legged series for the last two promotion spots. In all the playoff series, the lower-ranked club will play at home first. Whenever there is a tie in position (e.g. like the group winners in the Semifinal Round and Final or the third-placed teams in the first round), a draw will determine the club to play at home first.
The draw was held in the RFEF headquarters, in Las Rozas (Madrid), on 20 May 2013, 16:30 CEST.
The aggregate winners were promoted and qualified to the 2012–13 Segunda División B Final. The aggregate losers advanced to the second round promotion play-off for non-champions.