Jack Guy Lafontant (born 4 April 1961) is a Haitian politician who served as Prime Minister of Haiti from 21 March 2017 until 16 September 2018.^[1][2]

Lafontant studied medicine, specializing in gastroenterology and internal medicine and became a university instructor. He became a member of the Haitian Medical Association and the American College of Gastroenterology.^[3]

Lafontant is a member of the Rotary Club of Pétion-Ville, Port-au-Prince, and served as the group's president in 2016.^[4]

He was appointed as prime minister on 22 February 2017^[3] and presented his cabinet on 13 March 2017.^[5] His government obtained a vote of confidence from the Senate on 16 March and from the Chamber of Deputies on 21 March, with 95 votes for and 6 against with 2 abstentions.^[6] He assumed his responsibilities the same day his government won the vote of confidence.^[7] His position as prime minister was his debut in politics.^[8]

Following deadly mass protests against a government plan to raise fuel prices, Lafontant announced on 14 July 2018 that he had submitted his resignation to President Moïse, who accepted it.^{[9] [10]} Moise confirmed that he had accepted Lafontant's resignation and stated that he would work to find a new Prime Minister.^[10] He actually serves as caretaker.