The Tria Opuscula by the Late Antique Neoplatonist Proklos are accessible in full in the translation into medieval Latin by Wilhelm von Moerbeke, as well as in fragments in the Greek texts of Late Antique and Byzantine authors. Using the form of a commentary on passages, this work assesses what we can learn from these sources about the original Greek text of the three works. At the same time the commentary serves the elucidation of the first complete Greek retroversion of the Tria Opuscula, which is published here.