Caecilius, of Calacte (καλὴ Ἀκτή) in Sicily, Greek rhetorician, flourished at Rome during the reign of Augustus. Originally called Archagathus, he took the name of Caecilius from his patron, one of the Metelli. According to Suidas, he was by birth a Jew. Next to Dionysius of Halicarnassus, he was the most important critic and rhetorician of the Augustan age. Only fragments are extant of his numerous and important works, among which may be mentioned: On the Style of the Ten Orators (including their lives and a critical examination of their works), the basis of the pseudo-Plutarchian treatise of the same name, in which Caecilius is frequently referred to; On the Sublime, attacked by (?) Longinus in his essay on the same subject (see L. Martens, De Libello περὶ ὕψους, 1877); History of the Servile Wars, or slave risings in Sicily, the local interest of which would naturally appeal to the author; On Rhetoric and Rhetorical Figures; an Alphabetical Selection of Phrases, intended to serve as a guide to the acquirement of a pure Attic style - the first example of an Atticist lexicon, mentioned by Suidas in the preface to his lexicon as one of his authorities; Against the Phrygians, probably an attack on the florid style of the Asiatic school of rhetoric.

The fragments have been collected and edited by T. Burckhardt (1863), and E. Ofenloch (1907); some in C.W. Müller, Fragmenta Historicorum Graecorum, iii.; C. Bursian's Jahresbericht ... der classischen Altertumswissenschaft, xxiii. (1896), contains full notices of recent works on Caecilius, by C. Hammer; F. Blass, Griechische Beredsamkeit von Alexander bis auf Augustus (1865), treats of Dionysius of Halicarnassus and Caecilius together; see also J. Brzoska in Pauly-Wissowa, Realencyclopädie (1897).