World Bulletin / News Desk
The citizen, whose name was not given, was reportedly convicted on charges of "attempting to incite public opinion against the state" and "challenging sovereign decisions".
He was also convicted of "challenging judicial rulings" and "showing support for individuals detained for reasons related to terrorism and national security".
Targets of the convicted man's online criticisms reportedly included Saudi Arabia’s "Shura" system of governance and the kingdom's ongoing war against Shia rebels in Yemen.
In addition to the six-year jail term, the convicted man was also banned from using social media -- or the internet -- for a further six years after his release.
Wednesday's court sentence can still be challenged before an appellate court.