Efraïn Jonckheer (20 October 1917 – 30 March 1987) was a businessman and politician of the Netherlands Antilles.

Jonckheer served as Prime Minister of the Netherlands Antilles from 8 November 1954 until 14 February 1968.

As of 2022, Jonckheer was the longest serving Prime Minister in the history of the Kingdom of the Netherlands.

[4] In 1948 and 1952 until 1954, he was the representative of the Netherlands Antilles in the Round Table Conference about the future of the Dutch empire.

[8] On 15 December 1994, a statue of Jonkcheer was revealed on the Rif Fort in Otrobanda, Curaçao.