2018 Segunda División B play-offs

The 2018 Segunda División B play-offs (Playoffs de Ascenso or Promoción de Ascenso) are the final playoffs for promotion from 2017–18 Segunda División B to the 2018–19 Segunda División. The four first placed teams in each one of the four groups qualify for the promotion playoffs and the four last placed teams in Segunda División are relegated to Segunda División B. It also decides the teams which placed 16th to be relegated to the 2018–19 Tercera División.