post an anime character who you couldnt tell was a boy/girl the very first time you saw them

Finny from Kuroshitsuji.
I thought he was a girl, but his voice kind of sounded like a boy and girl at the same time. Also, those bobby pins made me very confused, and his eyes looked too big for a male character. He dressed like a boy, so I kept getting confused.

Inukashi from No. 6.
Her gender actually remains ambiguous for the whole of the anime. Characters use male pronouns to refer to her, but that could be an issue of translation (Japanese doesn't use pronouns as often as English.) Then again, she definitely does use male speech... but that could just make her a bokuko. It is, however, heavily implied that she's a girl. Although it's never addressed.

Taruto from Tokyo Mew Mew XD
I thought he was a girl the first time I saw him, but it turned out he was a boy...

Yukimura Kusunoki (Boku wa Tomodachi ga Sukunai)

Deidara from Naruto. I read the manga before I started watching the anime, so.. I didn't hear his voice and I thought he was a girl until I watched the anime and heard the male voice. ^^;

Nagumo Kaoru-kun

Bob from Fairy Tail
I thought this was a girl who is fat, bald, flat-chested, and has hairy legs, but... mmmaannn... I was totally wrong there...

Crona from Soul Eater XD dont get me wrong he looks like a girl

Makoto-kun from the anime the Idol M@ster..at first I thought she was he..not sure why,possibly the tuxedo mislead me in the first place when I saw it and her voice kind of sounded like a guy too..well kind of..then I found out that she was a she..

Nadeshiko/Nagihiko from Shugo Chara

Haku from Naruto.

Jun watarase from hapiness! i thought he was a girl but he is only crossdressing

Thread Master Kazuki - Getbackers

dnt het fooled by this cutie pic.....its a boy......& a deadly one

Ruka from Steins; Gate...i'm guessing i don't need to explain what i thought

Yuuta Sasaki from Cuticle Detective Inaba. I said "Aww, what a cute little girl!" Then I checked wikipedia. "... I mean, cute little boy."

Ranma

Mello from Death Note XD

I mistook Kanon from Umineko No Naku Koro Ni for being a female due to his facial features and also that his seiyū is female.

I also mistook Doll from the Kuroshitsuji manga for being male but in truth she is female. In Code Geass's manga, I mistook Lelouch Lamperouge for being female due to the drawing style. I thought he was a girl throughout the first volume until I heard his voice in the anime, then everything made sense in the manga to me.

Aoi-chan...really kept guessing on that one...-_-

Fon Master Ion from Tales of the Abyss

~Baka and Test
Clearly that is a girl lol

Haruhi

Don't get me wrong or anything, but while scrolling my fav. anime website for something to watch, I stumbled upon Inuyasha. I looked at the poster before the description, and I thought he was a girl.

Juuzou Suzuya from Tokyo Ghoul. The voice and looks made me believe he was a girl at one point. I actually had to look up the information to make sure he was a boy, and no other anime has made me do that

...
this one i think got alot of people as a boy...also dont know if someone already posted her

Gopher from Soul Eater. (even though it's a manga)
He was facing towards someone and he wears heels, so all I saw was the back of him...and he has long curly hair, soooo...

Freiza from Dragon Ball Z

SPOILER WARNING FOR ANYONE WHO HAS NOT SEEN OR HAS NOT FINISHED PERSONA 4 THE ANIMATION. YOU HAVE BEEN WARNED. SO NO COMPLAINTS ABOUT THIS POST. Naoto Shirogane. is a girl. All throughout the Persona 4 the Animation this character named kanji Tatsumi ends up taking a little liking to Naoto. And people mistook him for a queer gay guy. Even his otherself in the TV World Midnight Channel. Kanji's shadow version ended up showing Kanji's gay side. But it was revielded that Kanji is actually into girls later on in Persona 4 the Animation Episode 14 i believe it was. When Naoto Shirogane was faceing his other self shadow version. And the Persona 4 Dective gang the main characters of Persona 4. Yu Narukami,Yosuke Hanamura,Chie Satonaka,Kanji Tatsumi,Rise Kujikawa and Teddie used there Person's to rescue Naoto from the evil TV world. Which in the end turned back to a good world. Naoto's Shadow reviled that Naoto Shirogane is actually a girl trying to act all manly like a big shot man police detective. cause Naoto deep down inside is weak and cry's a lot. But the show never showed it. So Naoto joined the Detective police and became a man clothing and hair wise. And Naoto ends up becoming a strong character in Persona 4 the Animation. Here is the episode that proves Naoto Shirogane is a girl. link

Jakotsu from Inuyasha.