The 2017–18 Serie B (known as the Serie B ConTe.it for sponsorship reasons) was the 86th season since its establishment in 1929.
A total of 22 teams contested the league: 15 returning from the 2016–17 Serie B season, 4 promoted from 2016–17 Lega Pro (Cremonese, Venezia, Foggia, Parma), and 3 relegated from 2016–17 Serie A (Empoli, Palermo, Pescara).
On August 13, 2018, the FIGC decided to reduce the chronic financial instability of the league halting re-elections of clubs. Serie B was so reduced to 19 clubs.
Six teams could contest the promotion play-offs depending on the point differential between the third and fourth-placed teams. It began with a preliminary one-legged round played at the home venue of the higher placed team, involving the teams placed fifth to eight. The two winning (or higher placed team from regular season if a match ended with a draw) teams advanced to play the third and fourth-placed teams in the two-legged semi-finals. Those winning teams advanced to the two-legged final, where the winner was promoted to play in Serie A the following season. In the two-legged rounds, the higher seeded team played the second game at home.
Two teams contested the relegation play-out in a two-legged round. The higher placed team played the second leg at home. In the case of a tie on aggregate, the higher placed team from the regular season were declared the winners. The losers were relegated to Serie C for the following season.