This usually appears to advantage in anime/manga and I personally have no per se objections to guys with long hair in real life (by which I mean post shoulder-length), though it often happens that the examples I do come across, almost always, are more hippy/drug-users with that look. I am not sure why.

I should have pointed out that the hyperlink in my signature is divided into every genre MU has to offer, child porn and fan-comics aren´t literary genres, so i properly preach my genre-agnosticism.

It's (more than) okay in both. My own hair is now 70 cm long and i remember a time in the 90s when a huge amount of superheroes had long hair, so this is more than an anime cliché. Aquaman, Hawkman, Nightwing, Shadowman (most of Valiant actually), Turok, the Green Ranger, sometimes the Punisher and even Superman! A lot of villains also shared cool haircuts. Joker and the imprisoned Bane had a ponytail during Knightfall.
The trend never quite stopped, as Clark again had long hair during Future´s End or this week´s Rebirth flashback, and who knows what Snyder´s Justice League will bring.
These comics taught me how to read German and i quickly understood what my destiny was. To be the real life Simpsons Comic Book Guy, with beard and all! Where is my geeky Japanese waify? That ended up being his destiny in a recent season...
I only cut my hair (for 2 years) when i was in the military but insisted on keeping the beard, after basic traning. Me in 2015, ladies . (Note the Behelit.)
@chineserider I smoked exactly 1 joint in my life but i am quite liberal.

As a dude with long hair, I approve of other dudes with long hair.

Very random question. A better question would be why wouldn't it okay for guys to have long hair?

Well, i had long hair myself around 10 years ago. I still consider it to be normal haircut, just too much of a hassle looking after the hair. But if the guy's long hair look clean and neat then why not...

Don't care one bit. What's the length of hair matter, anyway? It doesn't make anyone look better or worse by default, and I don't think it's a specially feminine trait, either. (This from a girl whose own hair isn't even shoulder-length) It suits some people better than others, though; IRL and in fiction.

That being said, where I live only gangsters and vagrants grow their hair long, if at all, so if you asked me whether I'd ever have a relationship/friendship of any sort with a long-haired guy, the answer would be "No."

Hmm, I wouldn't care. What's more important to me is what kind of hair. Long hair that looks like you could slip on it? Not for me. Long and unkempt/too lazy to cut the hair? Also no. Anything else might be okay.

Also if I go to hair sites for men and lots will define long hair as actually long enough to touch the shoulder. I'd say it's not long enough to be called... long.

Wow, what a question

As a woman with a super short pixie cut that I have had on and off for the last seven years, I say if you can rock /work it then go for it.

It's only okay as long as you take care of your hair. Guy or girl. If it suits you, then bonus points. As a side note, guys who can rock man buns are awesome!

I'm a guy with long hair down to my waist. It's awesome and I get a lot of other folks compliment me on it. As a side note because of how rare it is, for most people it's pretty note worthy so people I meet once like at a store or such will often time greet me again like I'm a regular customer even if it's been weeks since I least visited. I'm also usually pretty nice, but there has to be plenty of nice folks so I can't imagine that's why they remember me.
It's kinda cool when all the eateries I go to know me as a regular when I really don't come that often. It gets me better service in many places.

Also in equal measure if anyone sees me from behind a lot of times they assume I'm a girl. I attribute that to my generally form fitting clothing I wear and my hair. It's usually pretty funny and just another thing to make a memorable impression.

Of course, it is okay. Doesn't matter whether it be in fiction or IRL. I'm not complaining if they either have long hair (or short hair). I mean, there is a guy I love who coincidentally have long hair...

Is it ok?
Sure.
Does it look good?
Depends on the bone structure & hair type.

Meh. Their choice. Don't really care~~~

People can wear their hair anyway they please. Now will it work for them? Like beards it all depends on style, the hair and physical features. Some can pull it off and others can't.

On a side note having long hair can be a real pain when dealing with those water saving shower heads. What used to take 5 minutes to wash the shampoo out can now take like 20 minutes which defeats the purpose of having a water saving shower head. I mean what the hell man

Now I'm curious about the opposite. What do you think of bald girls? Shame couldn't ask both things in a poll.

Don't care, it's their hair not mine. Shave it, grow it, w/e.

Lol. I don't care.

Prefer it long honestly. Unless you're balding. Flat top has to be the ugliest hairstyle.

It's fine as long as they take care of it. I see a lot of guys with long hair that's a greasy nasty mess, and they've never heard of conditioner or trimming dead ends. Of course in anime it's always neat/clean, if it's like that in real life guys can rock it.