Alexander, son of Numenius, was a Greek teacher and writer on rhetoric during the 2nd century CE, a period of Roman rule. He was a native of Seleucia in Cilicia and was active under the emperor Marcus Aurelius. He belonged to the cultural movement known as the Second Sophistic and was a student of the famous orator Herodes Atticus, which connected him to the leading intellectual circles of his day. According to the Byzantine encyclopedia called the Suda, he was a contemporary and rival of another sophist, Hadrian of Tyre, and lived to an old age.

His surviving work consists of technical handbooks for students of public speaking. He is credited with writing treatises with titles like On Figures, On the Arrangement of Parts, and On the Force of Enthymemes. These works focused on the mechanics of constructing persuasive speeches, analyzing rhetorical devices and the structure of arguments. None of his works survive in full; they are known only through fragments and references in the writings of later scholars.

According to modern scholars, Alexander’s significance lies in his role as a practical theorist and teacher. While not a celebrated performer, his systematic textbooks contributed to the formal training of orators. His association with Herodes Atticus highlights his place within a major network of rhetorical education. His writings continued to be used and cited by later teachers, indicating they served as useful guides within the long tradition of Greek rhetorical instruction.