So of the three seasons (https://tvtropes.org/pmwiki/pmwiki.php/SeasonalRot/LiveActionTV) where SNL is considered to be at their worst (https://tvtropes.org/pmwiki/pmwiki.php/DorkAge/LiveActionTV), which season was the worst of them?

Season 6 (https://en.wikipedia.org/wiki/Saturday_Night_Live_(season_6)) (1980-81). The first season without Lorne Michaels or any of the original cast (not counting Don Pardo), weird shock-value sketches that had no point except to offend (Leather Weather (http://snltranscripts.jt.org/80/80bleather.phtml), Commie Hunting Season (http://snltranscripts.jt.org/80/80brocket.phtml)), and Charles Rocket (the one who was supposed to carry the show) basically causing the end of Jean Doumanian's run due to the f-bomb uttered by him.

Season 11 (https://en.wikipedia.org/wiki/Saturday_Night_Live_(season_11)) (1985-86). Lorne's first year back, but with established actors (Robert Downey Jr., Anthony Michael Hall, Randy Quaid, Joan Cusack) who didn't have much if any experience in sketch comedy, and writing that just fell flat more often than not.

Season 20 (https://en.wikipedia.org/wiki/Saturday_Night_Live_(season_20)) (1994-95). The final season for Chris Farley and Adam Sandler (and Mike Myers who left midseason), who seemed to be basically sleepwalking through their sketches for the most part, and lots of low-brow humor. Even Chris Elliot and Mark McKinney (midseason add-on) couldn't help things.

I actually stopped watching SNL after season 5 because that's when all the original people left. I haven't heard much about seasons 11 & 20 but I've heard how bad season 6 was so I'd say that 6 was the worst.

In the early 1980's, 1980-82, Fridays was the show to watch.

Season 6 was the worst season for SNL. Seasons 11 and 20 are not the problem.

Season 6, for sure.

Season 6

19 was actuilly worse than 20 even with phil hartman in the cast so i will go off the board and say season 19

I haven't seen this show in 34 years. After Eddie Murphy left, it was horrible. Especially Billy Crystal in blackface doing Sammy Davis Jr in 1984.

I think it's universally agreed that Season 6 was the worst.

Season 11 comes in second. It was that bad.