Anonymous Seguerianus is the conventional modern name for an otherwise unknown rhetorician of the Roman Imperial period. The name derives from a manuscript note attributing the sole surviving work to "Sergianus" or "Seguerianus". Based on the treatise's content and style, scholars date the author to the first half of the 3rd century CE. The work's nature as a doctrinal compilation suggests the author was a teacher or practitioner operating within the standard Greco-Roman educational system.

The single extant work is the rhetorical handbook On Issues. It is a compilation focusing on the theory of stasis, meaning the central issue of a judicial case, and summarizes doctrines from earlier rhetoricians such as Hermagoras of Temnos.

The author's significance lies in the preservation of On Issues. This treatise is a valuable source for Hellenistic rhetorical theory, particularly for transmitting the influential but fragmentary doctrines of Hermagoras. It serves as a crucial link illustrating how classical rhetorical precepts were systematized and taught during the Roman Empire.