Olympiacos Football Club also known simply as Olympiacos, Olympiacos Piraeus, or with its full name as Olympiacos C.F.P. "Olympic Club of Fans of Piraeus", is a Greek professional football club based in Piraeus. Part of the major multi-sport club Olympiacos CFP, their name was inspired by the ancient Olympic Games and along with the club's emblem, the laurel-crowned Olympic athlete, symbolize the Olympic ideals of ancient Greece.
Their home ground is the Karaiskakis Stadium, a 32,115-capacity stadium in Piraeus.
Founded on 10 March 1925, Olympiacos is the most successful club in Greek football history, having won 45 League titles, 27 Cups (17 Doubles), and 4 Super Cups, all records. Τotalling 76 national trophies, Olympiacos is 9th in the world in total titles won by a football club.
The club's dominating success can be further evidenced by the fact that all other Greek clubs have won a combined total of 39 League titles, while Olympiacos also holds the record for the most consecutive Greek League titles won, with seven in a row in two occasions (1997–2003 and 2011–2017), breaking their own previous record of six consecutive wins in the 1950s (1954–1959), when Olympiacos was unequivocally nicknamed Thrylos ("The Legend").
Having won the 2014–15 league title, Olympiacos became the only football club in the world to have won a series of five or more consecutive championships five times in their history, a record that was praised by FIFA with a congratulatory letter of its president, Sepp Blatter.
They are also the only Greek club to have won five consecutive national Cups (1957–1961), as well as six League titles undefeated (1937, 1938, 1948, 1951, 1954, 1955).
Olympiacos is one of only three clubs to have never been relegated from the top flight of Greek football, and by winning the 2012–13 title, their 40th in total, they added a fourth star above their crest, each one representing 10 League titles.
In European competitions, Olympiaco's best performances are their presence in the UEFA Champions League quarter-finals in 1998–99, losing the semi-final spot in the last minutes of their second leg match against Juventus, as well as in the UEFA Cup Winners' Cup quarter-finals in 1992–93. The Red-Whites are by far the highest-ranked Greek club in the UEFA rankings, occupying the 35th place in Europe in the five-year ranking and the 31st in the ten-year ranking as of 2019, and one of the founding members of the European Club Association. Olympiacos won the Balkans Cup in 1963, at a time when the competition was considered the second most important in the region after the European Cup, becoming the first-ever Greek club to win an international competition.
Olympiacos is the most popular football club in Greece, also being the most popular club among the population of Athens, and gathering strong support from Greek communities all over the world. With 83,000 registered members as of April 2006, the club was placed 9th in the 2006 list of football clubs with the most paying members in the world; that figure increased to 98,000 in 2014. Olympiacos share a long-standing rivalry with Panathinaikos, with whom they contest in the "derby of the eternal enemies", the most classic football derby in Greece and one of the most well known around the world