Constantin II II tis Elládas, in '' [[Greek modern|Greek] : Κωνσταντίνος Β ΄ της Ελλάδας ) (born the June 2nd 1940], was king of Hellènes of 1964 with 1974.

It succeeded his father Paul {{Ier}}.

In 1967, a military coup d'etat founded the Dictature of the Colonels. However monarchy was preserved for the form while Constantin II was to take refuge in Italy. In 1973, Yeóryos Papadópoulos deposited officially the sovereign, showing it to have fomented an insurrection in the navy since its Roman exile. A " parliamentary republic présidentielle" was founded and Papadópoulos, only candidate, was elected president of the Republic for eight years.

With the fall of the dictatorship, because of the events of Cyprus, Constantin remained in exile. He was satisfied with televised interventions recorded since his exile in Great Britain. A referendum concerning the constitutional form of the mode took place in November 1974. Only 30% of the voters (mainly concentrated in the center Peloponnese very monarchist) decided in favor of the restoration. This referendum is regarded as freest of the six referendums concerning monarchy at the XXe century. The question is however still not distinct. Constantin was authorized to return in Greece for the funeral of his mother in 1981, but only for a few hours. In 1988, Konstantin Mitsotakis, leader of the New Democracy, publicly called into question “the impartiality” of the referendum of 1974. When Greece was in a political dead end in 1989, Constantin suggested that it was ready, if the Greeks wished it, to go up on the throne.

On the private level, king Constantin married the princess Anne-Marie of Denmark (sister of the current queen Marguerite II of Denmark) with which it had five children:

1. the Aléxia princess of Greece, Mrs. Carlos Morales - born on July 10th, 1965, she married Carlos Morales on July 9th, 1999. She has three children:
   1. Arrieta Morals there of Grecia (born on February 24th, 2002),
   2. Anna María Morals there of Grecia (born on May 15th, 2003),
   3. Carlos Morales there of Grecia (born on July 31st, 2005).
2. the crown prince (diadoque) Pavlos (Paul) to Greece - born on May 20th, 1967, he married on July 1st, 1995 Marie Chantal Miller of which he has 4 children:
   1. the princess María Olímpia of Greece (born on July 26th, 1996),
   2. prince Konstantínos Aléxios of Greece (born on October 29th, 1998),
   3. prince Akhíleas Andréas of Greece (born on August 12th, 2000)
   4. prince Odisséos of Greece (born on September 17th, 2004).
3. prince Nikoláos of Greece born on October 1st, 1969.
4. the Theodóra princess of Greece born on June 9th, 1983.
5. prince Philíppos of Greece born on April 26th, 1986.