The 2005–06 Primeira Liga season started on 19 August 2005 with a match between Sporting Clube de Portugal and Os Belenenses and ended on 7 May 2006. Futebol Clube do Porto was the new champion with 79 points, winning their 21st championship. The defending champion, Sport Lisboa e Benfica, was 3rd place behind Sporting and Porto.

The first goal scorer of the season was Rogério, who scored a 39th minute goal for Sporting against Belenenses. The first yellow card of the season was given to Sporting's Fábio Rochemback in the opening game of the season, and the first red card was given to Benfica’s João Pereira in an away draw against Académica de Coimbra.

Moreirense, Beira-Mar, and Estoril-Praia were consigned to the Liga de Honra following their final classification in 2004–05 season.

The other three teams were replaced by Estrela da Amadora, Paços de Ferreira, and Naval 1º de Maio from the Liga de Honra.

Pld = Matches played; W = Matches won; D = Matches drawn; L = Matches lost; GF = Goals for; GA = Goals against; GD = Goal difference; Pts = Points

The Primeira Liga (Portuguese pronunciation: [pɾiˈmejɾɐ ˈliɣɐ]), formerly called Primeira Divisão, currently named Liga ZON Sagres after their main sponsors, is the top professional association football division of the Portuguese football league system. It has a European ranking of 4th by UEFA's ranking of 2012 and a World ranking of 4th by IFFHS's ranking of 2011. The Liga ZON Sagres is presently contested by 16 clubs each season, but only five of them have won the title. Currently going into its 78th edition (counting four provisional championships in the 1930s), the competition is dominated by the nicknamed "Big Three" (Sport Lisboa e Benfica, Futebol Clube do Porto, and Sporting Clube de Portugal), who have a total of 75 titles, with Clube de Futebol "Os Belenenses" and Boavista Futebol Clube winning the other two.

Before the Portuguese football reform of 1938, an experimental competition on a round-basis was already being held — the Primeira Liga (Premier League) and the winners of that competition were named "League champions". Despite that, a Portuguese Championship in a knock-out cup format was the most popular and defined the Portuguese champion.

Tarik Sektioui (born 13 May 1977) is a retired Moroccan footballer and current manager.. A right winger, he was best known for his good control of the ball, technique, and speed. As a player, he spent most of his professional career in the Netherlands and Portugal.

Born in Fes, Sektioui played two seasons at French club AJ Auxerre, failing to establish with the main squad, and appearing sparingly for its reserves during his spell.

He arrived at the Netherlands and Tilburg's Willem II in January 2000, from Swiss outfit Neuchâtel Xamax, playing a major role with the club, eventually gaining club captaincy. In 2004–05, he switched to AZ Alkmaar in the Eredivisie. There, he scored some vital goals, forming a deadly partnership with Georgian striker Shota Averladze, and being scouted by Stade Rennais and Borussia Dortmund.

After an uneventful loan stint in 1999 with C.S. Marítimo, in July 2006, Sektioui returned to Portugal, after Co Adriaanse (also his coach at Willem) retrieved him from AZ to join country giants F.C. Porto. He would find the adjustment difficult and spent the second half of the season on loan to yet another Dutch club, RKC Waalwijk. On 3 February 2007 he played his first match for RKC, against NAC Breda.

Cristiano Ronaldo dos Santos Aveiro,OIH, (born 5 February 1985), commonly known as Cristiano Ronaldo, is a Portuguese footballer who plays as a winger or striker for Spanish La Liga club Real Madrid and is the captain of the Portuguese national team. Ronaldo became the most expensive footballer in history after moving from Manchester United to Real Madrid in a transfer worth £80 million (€93.9 million/$131.6 million). In addition, his contract with Real Madrid, in which he is paid €12 million per year, makes him one of the highest-paid footballers in the world, and his buyout clause is valued at €1 billion as per his contract.

Ronaldo began his career as a youth player for Andorinha, where he played for two years, before moving to C.D. Nacional. In 1997, he made a move to Portuguese giants Sporting Clube de Portugal. Ronaldo's precocious talent caught the attention of Manchester United manager Alex Ferguson, who signed him for £12.24 million (€15 million) in 2003. The following season, Ronaldo won his first club honour, the FA Cup. He also played at Euro 2004 with Portugal and scored his first international goal in the opening game of the tournament against Greece, in addition to helping Portugal reach the final. He was featured in the UEFA Euro All-Star Team of this competition.

Hassan Nader (born 8 July 1965) is a Moroccan retired footballer who played as a striker.

He spent most of his 21-year senior career in Portugal – amassing top division totals of 219 games and 94 goals – namely with Farense, where he surpassed the 100-goal mark in official games.

Born in Casablanca, Nader started his career with local club Wydad Casablanca, before signing with La Liga team RCD Mallorca in 1990–91. At the end of his second season, the Balearic Islands team was relegated, and he also had a run-in with manager Lorenzo Serra Ferrer during his spell.

In July 1992, Nader moved to Portuguese league side S.C. Farense, becoming the league's top scorer in 1994–95 with 21 goals, being influential in the Algarve side's UEFA Cup qualification. During eight years, he played in the team alongside compatriot Hajry Redouane.

Nader later moved to S.L. Benfica, but only appeared sparingly throughout two seasons and moved back to Farense, where he would remain until his 2004 retirement at the age of 39, as the team was relegated to the fourth level – he netted 11 league goals in his final year.