Our information about assessment behavior of EAP teachers constructing and using their classroom tests is so scanty that Schmitt and Hamp-Lyons (2015) believe it is hidden away from language testing community. We investigated how two different groups of Iranian EAP practitioners (discipline-area teachers and English language specialists) perceive and practice EAP assessment. We interviewed thirty teachers and examined forty test samples. Encouraged by our interview and corpus data and since achievement tests are inherently syllabi dependent, we content analyzed all undergraduate program syllabi. We found important differences pertaining to test tasks, type of knowledge to be assessed and features of good EAP tests between content specialists and English teachers. Iranian EAP teachers' assessment behavior seems to be attributable to their perceptions of goals of EAP courses as well as course objectives enshrined in syllabi contents. We discuss our findings and conclude with suggestions for EAP teacher-testers/assessment worldwide.