This article investigates Moroccan university students‟ grammatical competence. It verifies a hypothesis stating that after at least five years of explicit instruction of grammar, students should still retain grammatical knowledge. To do so, Swan and Baker‟s Grammar Scan Expert tests were administered to 73 students almost a year after their last course of grammar. Results show that they scored quite well in some structures and that they benefited from both explicit and implicit instruction. However, they scored lower than expected in the grammar structures covered in the four grammar courses they had taken in semesters 1 through 4.