Constitutional law
Hossain taught Constitutional Law and International Law at Queen’s College, Oxford (1957–59). He was a Research Student (1958-9, 1964) and Research Fellow (1977–79) of Nuffield College, Oxford and a Visiting Fellow (1976–77) of All Souls College, Oxford. He taught International Law and Constitutional law in the University of Dhaka (1962–67). He was a Visiting Professor at the Free University of Amsterdam (1997).