Adel Osseiran received his early education at the French Missionary Elementary School (Les Frères) operated by De La Salle Brothers in Sidon, and completed his secondary education at the International College (IC) in Beirut. He then pursued his higher studies at the American University of Beirut, graduating with a degree in History and Politics in 1928. He returned to his alma mater to do an MA in Political Science, graduating in 1936. During the interval, he had also begun a law degree at the Saint Joseph University (USJ) but did not complete it. A powerful orator in Classical Arabic, he was also fluent in English and French.