Why do girls and women refer to their female friends as "girlfriends," but boys and men do not refer to their male friends as "boyfriends?"?

Because most men would think that infers they are dating. Also, not all women call their friends girlfriends. I just say friend. Most of my friends are guys anyway.

I hear about “boys night out” or activities with “the boys,” but I’ve never heard a guy talk about his “boyfriends” (unless he’s gay and referring to romantic interests).

This, my good friend, is a great question.
In my opinion it is because woman tend to be more “social” than men and so they tend to create a supportive social circle of other women, who may, or may not, be bound to the core.
Thus, the mildly frivolous tag, “girlfriend” might apply.
Men tend hold back from truly intimate (not meaning sexual) relationships with other men until circumstances create a solid foundation of trust and confidence.
In which case, “boyfriend” , would almost be an insult to the quality of the relationship.
Plus, it sounds sort of gay. Not that there is anything wrong with that. But some straight guys would rather not get into the ambiguity.

^^ Very well said. However close the friendship may be still a friend will be called a friend and not a boyfriend.

Men are from Mars, women are from Venus. Women don’t stuff their junk into their girlfriends, so there is no sexual connotation. Men don’t normally stuff their junk into other men, as might be implied by the term “boyfriend.”

Because real male friends are not boy friends. They are bros.

Besides, “boy” may have a derogatory meaning among men, while women have no issue with “girl”. (most of them at least)

And girls tend to sport that annoying clingy clique behaviour, not usually shown among men.

I typically don’t call my friends girlfriends, but I’d imagine the reasoning is similar to what @josie gave.
When someone refers to another as their girlfriend, it implies they are very close. Probably because that is a term most boys use to refer to their significant other. I see girls that are best friends walk arm in arm/ hand in hand in the hallways at my school. They are close enough to do that. I never see boys do that. Most likely because they don’t want others thinking they are gay. Gay teenage boys get a lot of shit from other boys, from my experience. Probably because it’s seen as “Unmanly”

@avoice I don’t think that “Clingy clique behavior” is annoying. Maybe it’s because I get like that sometimes with my friends, but I think it’s just natural. The giggling and stuff is annoying, but that’s about it.

As a semi-related side note, it’s apparently becoming “offensive” for a straight woman to call another straight woman her girlfriend because it confuses LGBT people or something along those lines.

Haha, why do you think

Because it’s in the bible…

It is an american thing. A girlfriend in the UK is someone you are having a romantic relationship with. As is boyfriend. I don’t know what a girlfriend is when an american woman refers to ‘my girlfriend’. Is it a really good friend? Or a more casual acquaintance? It’s very confusing. Maybe you should all stop it :-)

Yeah, it’s another silly american thing British girls would never use that word ever.
So you see, nowt to do with us blokes getting all out of shape or banging our macho drum but still…

I always said friend for both. Boyfriend was reserved for someone I was dating. I only used girlfriend in a joking way. Like,“girlfriend, I know what you mean”. But never as an introduction. I would say this is my friend, followed by their name.
It became very confusing among lesbians. When they would introduce someone as their girlfriend, I never knew what type. Especially if I didn’t know for sure if they were gay.

There is no girlfriend in spanish. When dating someone you called them your Novia. Which stand for girlfriend (dating) or someone you are promised too, like engaged, or a bride. So you wouldn’t use it for your friends unless you are a gay female couple. Amiga, is for female friend and Amigo for male friend. Novio for boyfriend.