Rudolf Jozef Krol , also known as Ruud or Rudi, (born March 24, 1949 in Amsterdam) is a retired Dutch footballer who was capped 83 times for his country. He began his career at Ajax Amsterdam under the legendary Rinus Michels, and was part of the side (at left-back) alongside Johan Cruyff and Piet Keizer that reached the European Cup Final in 1969 against A.C. Milan. However, Krol missed the final due to a broken leg. He did however win 3 European Cups with Ajax, from 1971-1973. While others such as Cruyff and Johan Neeskens left for pastures new, Krol stayed at Ajax until 1980. (He later regretted staying so long). He moved to the NASL to play for the Vancouver Whitecaps, but stayed just one season. He then joined SSC Napoli where he played for in the next four seasons. His last club before he retired was the French club AS Cannes , and retired from club football in 1986.

Internationally, Krol made his Holland debut in 1969 against England, and earned 83 caps, retiring from international football in 1983. He was a crucial component in the Total Football side of the 1970's. A versatile defender, he could play in any position along the back four or midfield. In the , in which Holland reached the final, Krol primarily played at left-back and excelled - his creation of Cruyff's goal against Brazil and his 25-yard screamer against Argentina will live long in the memory. Alas, they fell at the final hurdle, losing 2-1 to West Germany.

By the time the 1978 World Cup came about, Krol had switched to playing as a sweeper and had earned the captain's armband after the retirement of Cruyff. Krol had a fine tournament, but was unable to prevent Holland from falling to their second Final defeat, this time losing 3-1 to Argentina.

Krol played for Holland as captain at the 1980 European Championship, but they disappointed, being knocked out in the first round by West Germany and Czechoslovakia. They also failed to qualify for the 1982 World Cup. He played for part of the qualifying for , and played his last international in 1983, in a 1-0 European Championship qualifiying defeat against Spain. His record cap haul was only surpassed by Aron Winter during the tournament.

In his managerial career, he has been head coach of Egypt, and has been assistant manager of Holland (under Louis van Gaal) and Ajax (under Ronald Koeman). He has recently acted as interim manager of Ajax, after the resignation of Koeman.