Which one was Dumb and which one was Dumber?

Lloyd is more talkative and assertive but he's definitely the dumber of the two. Harry just happens to be more passive which is why he tends to follow Lloyd's lead with their shenanigan's. Overall though, Harry is more equipped to be a functioning member of society. Beyond being incredibly dumb, Lloyd also tends to exhibit a degree of antisocial mental problems.

Harry is dumb, Loyd is dumber, that's the way I've always seen it. But I'm sure there's arguments for who takes the dumber crown by assessing certain actions taken by each character.

impossible to say it is.

Harry is Dumb and Lloyd is dumber. My opinion on why is because of the scene at the beginning where Lloyd gives his dead parakeet to a blind kid and Harry is able to understand it's wrong. But Lloyd is too dumb to see it as wrong. Also because of Lloyd giving Harry Laxative in his drink. That also makes him dumber.

Say what you will about Lloyd... but I feel like he was a lot more "cunning" (in an "evil way") than what Harry was (just considering this movie by itself). The trick he played on Sea Bass at the truck stop was genius, IMO.

I think Harry was "dumb" in a generally "sweet way"...but I think Lloyd had a really mean streak in him... which kind of made him an "evil genius" at times.