Seated Bronze Statue of Plato In Academy, located a mile outside walls of Athens, ca. 370-360 B.C. See Democratic Art: Portraits, Plato

Stewart, T120:
Diogenes Laertius 3.25 and 3.28 (work of early 3rd century A.D.)
In the first book of the Memorabilia of Favorinus it is stated that Mithradates the Persian set up a statue of Plato in the Academy and inscribed on it: "Mithradates the Persian, son of Orontobates, dedicated to the Muses this portrait of Plato, made by Silanion"
(The poet Amphis): "Oh Plato, all you know is to frown with eyebrows lifted high."

Simplicius, Physics 4.14 (commentary of 6th century A.D.), describes Plato as having a "fine shape of his nose, ... breadth of his body, ... (and) beauty of his eyes."

Ephippos (4th-century B.C. contemporary of Alexander the Great) is quoted by Athenaios (11.509 c-d) as stating that one of Plato's pupils had "well trimmed hair and a long beard," a hairstyle that is consistent with portraits of Plato.