John M. Systermans (died May 28, 1989) was born Jean-Marie Systermans, but was better known as Father Henry Systermans or Pater Henri Systermans. He was a 20th-century Belgian-born missionary and priest with the Congregation of the Sacred Hearts of Jesus and Mary.He served for most of his life in Hawaii most notably during the 1950s at the leper colony at Kalaupapa on Molokai. His service there followed in the tradition of fellow Belgian priest, Saint Damien, and his contributions were part of the research gathered by Gavan Daws for the definitive biography Holy Man: Father Damien of Molokai.