Theodore Styppeiotes (Greek: Θεόδωρος Στυππειώτης) was a high-ranking bureaucrat of the Byzantine Empire and a member of the court of Emperor Manuel I Komnenos (r. 1143–1180), acting as the Emperor's grammatikos or secretary.
Styppeiotes became an influential figure while serving as the assistant of John Hagiotheodorites, but through intrigue managed to have Hagiotheodorites sent to serve as the civil governor (praetor) of the joint theme of Hellas and the Peloponnese. Praised by Theodore Prodromos for his trustworthiness as a scribe in guarding secrets, Styppeiotes rose from one office to the next, eventually reaching the position of kanikleios, guardian of the imperial inkstand. From this position, he was able to influence Manuel due to his close proximity to the emperor. Standing high in Manuel's favour, Styppeiotes became the mesazon, essentially chief minister and head of the civil administration.
In 1158/9, however, while on campaign in Cilicia, Manuel ordered Styppeiotes to be arrested and blinded. The reasons for this act are unclear, with different reasons being given by contemporary authors. According to John Kinnamos he publicly announced some kind of prophecy according to which Manuel would die soon, and that "the Roman senate should no longer grant power to a strapping young man, but to a man of properly advanced years, in order that under him, ruling by the letter [or by learning] the affairs of state might be managed as in a democracy". The German chronicler Rahewin, on the other hand, reports that the kanikleios had hired three men to assassinate Manuel, but that the empress discovered the plot and informed the emperor. Niketas Choniates gives a rather different account, which according to the historian Paul Magdalino may represent the "unofficial" version of the affair, but the details of which were proven to be mostly fictitious by the Byzantinist Otto Kresten. According to Choniates, Styppeiotes' downfall was the result of his rivalry with John Kamateros, the logothetes tou dromou, who became frustrated with the special relationship between Styppeiotes and the emperor; Styppeiotes's goals were being fulfilled through his constant ties to Manuel while Kamateros's limited access to the emperor resulted in his demands never being met. Kamateros therefore forged a correspondence between Styppeiotes and the Norman king of Sicily, William II (r. 1166–89), which he hid so that it could be discovered easily. Styppeiotes was ultimately charged with treason by Kamateros, resulting in Emperor Manuel having Styppeiotes blinded and his tongue severed. Styppeiotes' downfall coincided with the blinding of Michael Glykas and the escape of the emperor's cousin and future emperor Andronikos I Komnenos (r. 1182–85), and although the Byzantine sources make no explicit connection, it is very likely connected to both events. As a result it may indicate, according to Magdalino, both of a faction at court which desired a return to a more consensus-based mode of ruling, with the emperor consulting with the Senate as was the practice before the rise of the Komnenoi, as well as of a pro-Sicilian faction opposed to Manuel's pro-German stance, manifested in his alliance with the Hohenstaufen and reinforced by his empress, Bertha of Sulzbach.