José Romão Martenetz (born Roman Martynets; Ukrainian: Йосиф (Роман) Мартинець) (7 February 1903, Lviv, present Ukraine – 23 February 1989, Curitiba, Brazil) was a bishop of the Ukrainian Catholic Eparchy of São João Batista em Curitiba (1962–1978) and a monk of the Order of Saint Basil the Great.
On return to Transcarpathia, he was Director of Studies at Maliy Berezny and prefect of students in the Minor Seminary of Basilian fathers in Uzhorod.
In 1953 Martenetz returned to Rome where he served the governing Proto-Archimandrite of the Basilian Order and was rector of the Ukrainian Pontifical College of Saint Josaphat on Janiculum (1953–1955).
On 10 May 1958 Pope Pius XII appointed him as Assistant Bishop to Cardinal Jaime de Barros Câmara, Archbishop of Rio de Janeiro who also was the ordinary of all Catholics of Oriental Rites in Brazil, and his episcopal ordination took place in Rome on 15 August 1958 in Rome in the Church of Saints Sergius and Bacchus.
On 10 May 1978, Martenetz, already weak and sick, gave his resignation to Pope Paul VI and the episcopacy of Curitiba was transferred to Bishop Krevey.
Martenetz then went to live in the seminary of Basilian Fathers in Curitiba, where he was confessor of students and also taught Ukrainian language and literature.