Everybody else here is entirely incorrect, and it's unbelievable to what a degree.

"LOL" is the signular form, and "LOLZ" is simply the plural.

Meaning "lol's" or more than one "lol".

Adding a lowercase "z" at the end (Proper form, LOLz, or LoLz to switch between capitals and lowercase as is commonly done by a number of prepubescent horny teens, namely girls) does not necessarily add another word to the acronym. Just like if I were to write to you about "STDs", I would not be talking about Sexually Transmitted Disease Succotash, but rather multiple Sexually Transmitted Diseases.
Here in teh intranets, teh misconsepshins are teh commonplace, LoLz.
by Vincealicious November 12, 2006
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So this one definitely needs and update ; )

According to multiple super-reputable online sources, all of which are beyond reproach (LOLz)! These are the most common uses.

1) LOLz is meant as a sarcastic response.

2) Its secondary intent is dubious but remains insincere.

3) Lastly, some say it’s a plural form of LOL. Although this is not the main definition, it is widely used. This definition makes the least sense considering laughing out loud is of lots of laughs, LOL!

A funny side note, LOL was originally used in the pre Internet days as an abbreviation for lots of love. Following the advent of chat rooms and instant messaging this quickly mutated into lots of laughs and laugh out loud.

Other less common uses for LOLz include laugh out loud zone and laugh out loud zebras (so ridiculous).
1) In example: Marks statement - “Dan, I most definitely am the best at all sports video games” Dan response - “You’re absolutely right Mark, I didn’t just beat you at NHL Hitz the last ten straight times, LOLz!”

2) For instance, when you’re out for a day of paintball and someone posts in a group chat: “Its all fun and games till someone gets an eye shot out!” The words fun and games could be replaced with LOLz. Also, whoever it was that posted that message should be shot by everyone in the group many times….LOLz!
by Big-Daddy-Blue August 4, 2016
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LOL (Laugh Out Loud) but with a Z.
Guy 1 "I'm sorry your cat passed away."

Guy 2 "Thanks,...he died so young."

Guy 1 "How did he die again?"

Guy 2 "He was runned over by a tri-cycle while chasing someone with a....twinkie.

Guy 3 " LOLZ"
by AwayWeGo April 12, 2010
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Funnier then just plain LOL
Example Guy says:
An example thats funny

Example Guy2 says:
by Wayne Edwardo January 21, 2009
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The high increase in popularity of the infamous LOL (laughing out loud) was not enough for the teenage, trying to be cool, defying mom and dad, often emo generation. They had to come up with something even cooler and that's how LOLZ was born. Some say that Z stands for S, therefore it's the plural version of LOL. But let's analyze that thought process a bit. The plural of LOL would be translated as "laughing out loudS" or "laughingS out loud" which, for the few of us who are at least trying to be grammatically correct makes as much sense as "z" being used as a replacement for "s".
In this case, the Z could be interpreted as the initial of a completely different word. Possibilities:

1. Laughing out loud ZBANG! - this would indicate that the violent laughter has caused the person to fall and hit the ground, thus creating a loud sound;
2. Laughing out loud ZTUPID - seeing as Z is so often used as a replacement for S, it makes sense. It's also a very positive thing, when you consider that admitting you have a problem is the first step to recovery;
3. Laughing out loud ZENITH - the person doing the laughing has entered a state of astral trance...
A: - I'm a complete idiot, with absolutely 0 knowledge about anything even remotely intelligent
B: - Lolz
by Alinutza March 21, 2008
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Laughing out loud zillions of times like a moron. Skinny, tall, white males in their early twenties do this. They tend to post "LOLZ" on other people's Facebook walls while interrupting a conversation between other people and pretend they patented the phrase. Really, the term "LOLZ" is just another way of saying they are lacking down below. LOLZ
Fred: I saw a funny commercial the other day, it made me laugh.
Juan: Was that the one with the big dog?
Fred: Yea, that was it!
Andrew: LOLZ! Hey guys, can I be included in this conversation?
by ANDYLAMA December 10, 2010
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