Progress in skull-base endoscopic surgery has improved our knowledge of olfactory cleft (OC) anatomy. This article presents a review of current knowledge concerning the OC roof: descriptive anatomy, radiological exploration, and endoscopic observation. The OC is a narrow area in the most superior part of the nasal cavity. Its roof is the thinnest structure separating the nasal cavities from the brain; it comprises three superimposed tissues: nasal mucosa, ethmoid cribriform plate (ECP), and dura mater. The ECP comprises the anterior ECP containing the ethmoidal slit (ES) medially and the cribroethmoidal foramen (CEF) laterally; and the posterior ECP, comprising the olfactory foramina. The OC roof is bordered anteriorly by the nasal bone roof, laterally by the lateral ethmoid masses, and posteriorly by the jugum and anterior wall of the sphenoid sinuses. Imaging is crucial for analyzing this wall, providing precise detailed information on conformation and anatomic relations with adjacent structures such as the anterior ethmoidal artery. Understanding OC roof anatomy and correct interpretation of imaging are essential for safety in present-day functional endoscopic sinus surgery and anterior skull-base oncologic surgery.