What is your pick?
For me the 1970s, basically for Peter Sellers.

For me it's the 1930's...Marx Brothers, W.C. Fields, The Three Stooges, Mae West, Screwball Comedies, Chaplin, Laurel & Hardy....an amazing decade for comedy.

Voted 80s, but I suppose a lot of movies I think of as '80s' are actually late 70s.

1890s

Ditto on all of them, plus Eddie Cantor, who did great comedies in the '30s (e.g. ROMAN SCANDALS, THE KID FROM SPAIN, KID MILLIONS), and Joe E. Brown, who was, at the time (early-to-mid 1930s), the top comedy star at Warner Bros. and far more popular with the moviegoing audience than Fields, West, and the Marx Bros. combined. Brown was an ex-vaudevilian and an athlete and his films were filled with strenuous physical comedy. People who only know him from his later character roles like SHOWBOAT (1951) and SOME LIKE IT HOT (1959, in which he delivers the final line), would be surprised at seeing him do his own slapstick stunts in his starring roles in the '30s (e.g. YOU SAID A MOUTHFUL, FIREMAN SAVE MY CHILD, EARTHWORM TRACTORS, ALIBI IKE, ELMER THE GREAT).

The '30s also gave us Max Fleischer's Betty Boop and Popeye cartoons and the beginnings of Warner Bros.' Looney Tunes and Merrie Melodies. Daffy Duck and Porky Pig got their start in the 1930s, as well as the nascent form of Bugs Bunny ("Hare-um Scare-um," "Porky's Hare Hunt"). Tex Avery made some of his funniest cartoons in the 1930s (e.g. "Hamateur Night").

It was a toss-up between the 1920's and the 1930's for me. I ended up going with the 1930's but if I were to vote tomorrow it could easily go another way.

Very odd to choose the 1970's based on Peter Sellers. He hit his prime in the 1960's, and his comedic output in the 1970's was pretty sketchy IMHO.

I'm going with the 1980s simply because my two favorite comedies come from that decade: Airplane! (1980) and The Naked Gun (1988)

80's - not even close.

70s: Young Frankenstein, Animal House, Blazing Saddles, The Jerk

No real interest in films prior to the 60's aside from Japanese classical; so with what I am left with it would easily be the 80's when the humor became raunchier and in some cases, darker.

Better off Dead
The Ninth Configuration
Fletch
The Burbs
Real Genius
Trading Places
Porkys
Raising Arizona
Night Shift

...all favorites.

80's... John Hughes' body of work alone made the decade.

I'll take Marx Bros. DUCK SOUP over Hughes teen movies any day.

I can't believe I agree with wm lopez on something.

Absolutely

1980's:

Caddyshack, Stripes, Fast Times at Ridgemont High, Risky Business, Airplane, Fletch, Planes Trains and Automobiles, Ghostbusters, Back to School, Easy Money, Weird Science, Ferris Buellars Day Off, Breakfast Club, Sixteen Candles, Trading Places, 48 Hours, Beverly Hills Cop.

That's off the top of my head

Immediately when I saw the thread title. My first thought was the '30s. And I still haven't seen a good chunk of those flicks. Chaplin alone is enough to mark that decade. Add in the others and well....it's an amazing decade for sure.

I picked the 1930s due primarily to the Marx Bros. and the classic screwball comedies. But it was a toss-up with the 1970s for me, due to Monty Python's movies and Woody Allen's "earlier, funnier" movies, so that decade would be a very close 2nd (so close, it's practically a tie).

I'd add:

Car Wash
Play It Again, Sam
Life of Brian
Monty Python and the Holy Grail
The Bad News Bears
MASH
Being There
Slap Shot
North Dallas Forty

And, of course...

Meatballs

Because of National Lampoon, the 80's wins easily. The only film that may be in the late 70's might be "Animal House" Between National Lampoon and John Hughes, the 80's ruled for oddball comedies that stand the test of time:

Stripes
Caddyshack
Vacation
Blues Brothers
Animal House
Sixteen Candles
Weird Science
Ferris Bueller's Day Off
Fletch
etc.

1930's for sure.

Well he was the primary factor to choose that period but not the only one... it was a tough choice between the 60s and 70s and i'd go for the other another day. I thought George C Scott was the funniest in Dr. Strangelove btw and liked Sellers' more extreme style later on.

Top 3 would be
70s
60s
30s

None of those movies are rated "G". And all the 30's did their comedy with out bathroom humor which is hard to do.
So more talent and artwork goes to the 30's.

And let's not forget the films by Dwain Esper!

Pulling off bathroom humor effectively is hard to do as well.

It's hard to decide between the 70's and the 80's. My two favorite comedies are Young Frankenstein and Naked Gun. If I have to choose, I'll use The Blues Brothers as my tiebreaker movie, and say the 80's.