There have been so many awesome sitcoms it's hard to pick the funniest of all time. I used to change my opinion based on which show I had watched most recently. A lot of younger people aren't familiar with the comic genius of The Andy Griffith Show, The Honeymooners, Newhart and many of the other older shows.
Seinfeld is at the top of many lists and it was definitely a great show. I just watched the series finale of Schitt's Creek and will miss it dearly. That show has to be somewhere on every top ten list. However there is one show that I think is the funniest of them all.
Veep, starring Julia Louis-Dreyfuss is at the top of my list. The show is insanely funny. The acting is superb. I don't think there was 1 bad episode in the whole series. The writing was at "genius" level. If you never saw it, now is a great time to binge watch it while HBO is offering 500 hours of free streaming of selected shows on HBO NOW. A word of warning--it's not kid friendly-- but it is truly hilarious,