Amsterdamsche Football Club Ajax (), also referred to as AFC Ajax, Ajax Amsterdam or simply Ajax (after the legendary Greek hero), is a professional football club from Amsterdam, Netherlands. The club is historically one of the three clubs that dominate the Dutch national football league (Eredivisie), the others being PSV and Feyenoord.

Ajax is historically one of the most successful clubs in the world; according to the IFFHS, Ajax were the seventh most successful European club of the 20th century. The club is one of the five teams that has earned the right to keep the European Cup and to wear a multiple-winner badge; they won consecutively in 1971–1973. In 1972, they completed the European treble by winning the Dutch Eredivisie, KNVB Cup, and the European Cup; to date, they are the only team to keep the European Cup and accomplish the European treble. Ajax's last international trophies were the 1995 Intercontinental Cup and the 1995 Champions League, where they defeated Milan in the final; they lost the 1996 Champions League final on penalties to Juventus.

They are also one of three teams to win the treble and the Intercontinental Cup in the same season/calendar year;with Manchester United in 1999 and FC Barcelona in 2009. This was achieved in the 1971–72 season.UEFA sanctioned the UEFA Supercup for the first time in 1973. In 1972 was an unofficial edition and the I Centenary of Rangers (see History of the UEFA Supercup in uefa.com). Ajax, Juventus and Bayern Munich are the three clubs to have won all three major UEFA club competitions.(European Cup, Cup Winners' Cup and UEFA Cup) They have also won the Intercontinental Cup twice, the 1991–92 UEFA Cup, as well as the Karl Rappan Cup, a predecessor of the UEFA Intertoto Cup in 1962.UEFA sanctioned the UEFA Intertoto Cup for the first time in 1995. In the 1960s, it was unofficial. See History of UEFA Intertoto Cup in uefa.com.

This list includes current and former football clubs who have entered partnership agreements with Ajax Amsterdam.

Current affiliated clubs

Almere City

Almere City FC are a club from Almere, Flevoland, situated only 21.9 miles (35.2 km) away from Amsterdam, and playing in the Dutch Eredivisie, the 1st tier of professional football in the Netherlands. The partnership between the two clubs began on 1 July 2005, with their first contractual agreement lasting until 30 June 2010, bringing with it an intense collaborative effort between the two sides. The close geographical proximity of the two clubs, allows for young Ajax players to be loaned out to Almere without having to travel to far from their homes. Their partnership focuses on the youth teams, and exchanging emerging players from both sides, as well as sharing mutual coaching seminars and exchanging coaching methods. Several of the emerging players of Jong Ajax who require more playing time at a higher competition level than the youth leagues, are subsequently loaned to Almere City FC where they can play in the Dutch Eerste Divisie instead, in order to gain valuable playing experience. On 11 May 2010 a contract extension was agreed upon between the two clubs, extending their partnership until the summer of 2015.

On 11 October 2012, former Ajax player, Jong Ajax trainer, and then manager of Ajax U-19 Fred Grim was announced as the newly appointed manager of Almere City further strengthening the relationship between the two clubs.

Barcelona

FC Barcelona are a Spanish club playing in La Liga, the top-flight of football in Spain. The relationship between Ajax and Barcelona dates back to the early seventies, when footballing innovators Rinus Michels and Johan Cruyff made the move over to coach and play for the Catalan footballing giants. Over the years several Ajax players and managers have followed in their footsteps, and made the move to Barcelona, such as Patrick Kluivert, Marc Overmars, Frank de Boer, Ronald de Boer, Frenkie de Jong and Louis van Gaal amongst others.

On 2 June 2007, Technical director Martin van Geel announced that the two clubs would work closer together, sharing similar values and footballing philosophies, the focus of the partnership will be to exchange information amongst the technical, medical and coaching staff of the two clubs. The partnership with Barcelona is unique for Ajax, since it is the only affiliated club, where Ajax is not the mother-club. The relationship focuses more on the youth development of Barcelona players. Young players from FC Barcelona B, who are not yet ready to make the step to the first team can be loaned to Ajax for a season to obtain valuable playing time in the Eredivisie, rather than playing in the Segunda División in Spain. Former players such as Gabri and Oleguer have also moved to Amsterdam following successful stints in Barcelona as well.

On 31 January 2013 under newly appointed Technical Director at Ajax Marc Overmars, the young winger Isaac Cuenca was loaned from Barcelona for the remainder of the season, while Bojan Krkić was loaned to Ajax the season following. On 4 November 2014, an interview with Barcelona president Josep Maria Bartomeu was published in the Dutch news publication De Telegraaf, where he refers to the Spanish club as the "Son of Ajax". He explained the influence Michels and Cruijff had on the club as being imperative in creating the infrastructure and culture present at the club today.

Cruzeiro

Cruzeiro EC are a Brazilian club from Belo Horizonte, Minas Gerais playing in the Série A, the top flight of football in Brazil. The partnership between Ajax and Cruzeiro was announced on 14 December 2007, and serves as a sort springboard for Cruzeiro players who seek to play their professional football in Europe. Young players from the club are regularly invited to Amsterdam for trial periods, and in case Ajax decide to purchase a player from Cruzeiro, the Brazilian side then retain 35% proprietorship and transfer rights of the player. Furthermore, the two clubs organize exhibition matches between their senior, and more frequently their youth teams, to help promote international playing experience for their players. Both former Ajax players Zé Eduardo and Maxwell were acquired from the club in the past.

Beijing Guoan

Beijing Guoan are a Chinese club from Beijing, playing in the CSL, the top flight of football in China. On 15 December 2007 AFC Ajax and their then main sponsor Aegon announced a partnership with Beijing Guoan to take immediate effect. The purpose of the collaborative effort is to strengthen the AFC Ajax brand in China, but also to help improve the quality of the team's youth development, and to allow young talented Chinese players the opportunity to come perform in Amsterdam on trial periods.

Palmeiras

Palmeiras are a Brazilian football club from São Paulo, playing in the Série A, the top flight of football in Brazil. On 10 January 2010 it was announced by Rik van den Boog and Marcelo Solarino that AFC Ajax and Palmeiras had agreed to collaborate and to share information regarding each other's coaching, technical and medical staff. The partnership focuses primarily on improving each other's youth teams, creating an exchange program, where the youth teams participate in each other's offseason tournaments in order for the players to obtain valuable international experience and exposure. Furthermore, players from the Brazilian club are invited for trial periods in Amsterdam offering an opportunity for the players to make the move to Europe if they are able to convince during their visit at De Toekomst. Ajax also retain first choice for players that Palmeiras are looking to sell in this joint venture between the two clubs.

On 14 January 2012, Palmeiras and AFC Ajax played their first competitive match, when Ajax paid a visit to the Brazilian club for the first time since entering this partnership. The match was played at Estádio Palestra Itália, Palmeiras home stadium, where the match ended in a 1–0 win for the Brazilian side.

AS Trenčín

AS Trenčín is a Slovak club from Trenčín playing in the Fortuna Liga, the top flight of football in Slovakia. On 12 December 2012 it was announced, that Ajax and Trenčín would form a partnership, agreeing to a contract that would bind them until 2014. The Slovak club is owned by former Ajax player and Johan Cruyff's good friend Tscheu La Ling. The purpose of the partnership is to share scouting information between the two clubs, for them to keep each other informed over the developing talent in each other's respective regions. In 2013, Stanislav Lobotka was loaned to Ajax, while Gino van Kessel was sent to the Slovak club on a loan deal in return.

Guangzhou R&F

Guangzhou R&F are a Chinese club from Guangzhou playing in the CSL, the top flight of football in China. On 27 November 2017 it was announced, that Ajax and Guangzhou R&F would form a partnership, agreeing to a contract for five years.

Sagan Tosu

Sagan Tosu are a Japanese club from Tosu, Saga on the Kyushu island, playing in the J1 League, the top flight of football in Japan. On 26 January 2018 it was announced, that Ajax and Sagan Tosu would form a partnership, agreeing to a contract for three years. The purpose of the relationship is to strengthen the youth development of the Japanese club with the help of the Ajax Coaching Academy (ACA). On 11 April 2018, Ajax eSports player Bob van Uden was loaned to Sagan Tosu for a season, to compete in the e.J1League.

Sydney FC

Sydney FC are an Australian club from Sydney, New South Wales playing in the A-League, the top flight of football in Australia. On 3 April 2018, it was announced that Ajax and Sydney FC had signed an agreement for a partnership of three years. The aim is to improve the youth academy of Sydney with the help of Ajax and to give the Amsterdam club a scouting platform in the country. On 23 August 2018, Ajax marquee Siem de Jong was sent to Sydney FC on a season-long loan spell.

Sparta Rotterdam

Sparta Rotterdam is a Dutch club from Rotterdam, South Holland playing in the Eredivisie, the 1st tier of football in the Netherlands and also the same tier as Ajax. On 25 October 2018, it was announced that Ajax and Sparta had agreed to a partnership of three years, to help further develop the youth academy of the Rotterdam club and allow a path for youth players to make a transfer to Amsterdam. The Sparta Youth Academy is one of the strongest in the country, having received a four-star academic sports certification, the highest possible in the country. Despite having benefits for the Rotterdam side, the announcement received backlash in response from Sparta-supporters, mainly due to the city rivalry between Amsterdam and Rotterdam.

Sharjah FC

Sharjah FC is a United Arab Emirates club from Sharjah playing in the UAE Pro League, the top professional football league in the United Arab Emirates. On 5 January 2020, it was announced that Ajax and Sharjah had agreed to terms on an official partnership. The purpose of the partnership is to improve the youth academy of the Emirates club and to raise the skill level.

Pachuca

C.F. Pachuca is a Mexican club from Pachuca playing in the Liga MX, the top professional football league in Mexico. On 5 August 2022 it was announced that Ajax and Pachuca had agreed to terms on an official partnership. The purpose of the first partnership deal, closed by Klaas-Jan Huntelaar and Armando Martínez, is to improve the youth academy of the Mexican club and scouting in the region.

Gamba Osaka

Gamba Osaka is a Japanese club from Osaka playing in the J. League, the top professional football league in Japan. The purpose of the collaboration is to improve on identification of talent, and the development of players at an early stage.

Various HETT-clubs