The 2005–06 Segunda Divisão season was the 72nd season of the competition and the 56th season of recognised third-tier football in Portugal.
[1] The league was contested by 58 teams in 4 divisions with CD Trofense, AD Lousada, UD Oliveirense and CD Olivais e Moscavide winning the respective divisional competitions and progressing to the championship playoffs.
The overall championship was won by CD Olivais e Moscavide and the runners-up CD Trofense were also promoted to the Liga de Honra.
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The final was played on 28 May 2006 in Marinha Grande.