A definite No.
James was Harry's real father. There is no evidence at all in the books to suggest otherwise.

Lets leave out all the obvious points raised by the other Quorans about Harry looking just like James.
Lets look at the entire story in Lily Potter's point of view.
Lily befriended the most unpopular boy even though he was getting involved with future Death Eaters and then stopped talking to him once he used the M-word. She later married James Potter and joined Order of Phoenix which was formed to stop Voldemort.
So Lily and Snape were in the opposite side of warring forces. Why would Lily cheat her pure blood husband who is ready to fight for the rights of Muggle Borns with a half blood Snape who joined a leader who hates Muggle Borns ,especially when she herself was a Muggle Born?
I guess you are insulting Lily Evans to think she would do that.
Lol
First of all;
Although I think this would make interesting FanFic material, I don’t see this “theory” as legitimate.
Actually, I'd say he definitely is, yes.
If you read the novels *carefully,* there's many clues scattered throughout the series.
The most glaring, obvious one is that Rowling practically shouts at the top of her lungs at one point that Snape had "messy, thick, black hair" - just like Harry.
Add a little life experience, the fact that Harry looks nothing like his supposed father but does resemble Snape in both certain personality traits and appearance, the situation between the three in the love triangle, Snape's protectiveness of Harry, his deep love for Harry's mother, the way he distances himself and yet keeps an eye on him -
Yes. It's obvious. :)
NO.
Severus Snape was madly in love with Lily ever since he was a child. Lily always believed that James Potter is a bully and she never agreed to even go out with Severus for one simple reason because he had ruined all chances with her by calling her a mudblood.
She was certainly not in love with the eleven year old Severus who called her cute or the man who protected her son after her death. She was driven away by the man who was indulged with the Death Eaters.
So no, Harry Potter is not the son of Severus Snape and Lily Evans. For one, Harry was the youngest seeker and one of the best during his time which is a strong resemblance of his father, James.
Harry has been constantly reminded that he’s inherited his mother’s eyes. Whereas, he’s also been complemented of looking more like his father. Even Sirius had a hard time distinguishing James’ appearance from Harry.
If Harry Potter was Snape's son he wouldn't look like James, his last name would be Snape—his middle name wouldn't be James—his first name would be anyone's guess, and he would have a totally different personality. In other words, he wouldn't be Harry Potter, he'd be an original character.
Even if you were to presume that Lily was a horrible person who cheated on James and pretended Snape's baby was his and still named the baby Harry, you'd still have the fact that the child would look totally different and would have a totally different personality. In other words, he'd still be an original character.
Not to mention that Lily's personality would have to be so different that she would be more or less an original character too... i.e what is commonly known as out-of-character.
No matter what scenario you go with, all of the above is true and there's no way in hell that one could pretend that Harry in the books and films is Snape's son.

NO. GOD, NO!!
I’m really tired of this stupid fan fiction myth.
Voldemort is Harry’s real father. Snape is Harry’s real father. Hagrid is Harry’s real father. Joe Montana is Harry’s real father. Freaking Aragog is Harry’s real father!
The fact is, no where does it ever say that in the books. Sorry pal, but that’s the way it is.
Although it would be a hilarious scenario to imagine Aragog as Harry’s real father.
No, Sanpe wasn't Harry's dad.
And in case you're wondering, Fawkes wasn't Hedwig's brother.
Madam Maxime wasn't Flitwick's mum.
Dumbledore wasn't Crabbe's grandfather.
Umbridge wasn't Fleur's sister.
Cedric wasn't Dobby's uncle.
Last but not the least, Voldemort wasn’t Delphini's dad because let's not accept the fanfics that don't make sense.
Harry looks like his James, has his James’ hair and glasses and talent for Quidditch. He hates Slytherins. He is brave and doesn't plan on joining Death Eaters anytime soon
Yep, the Head of Slytherin Potions Master is definitely Harry's father
(it was Sarcasm if you didn't understand)
I really don’t know why anyone would even think that Harry was Snape’s son. Harry’s resemblance to James was uncanny. Why would Snape’s son look like James? Don’t give me the whole Harry was charmed to look like James shit, cause that’s a terrible explanation that I only find in terrible fanfiction. Harry’s face couldn’t have been charmed permanently. It would have come back to resemble Snape at some point.
Even if you say his face was charmed to look like James permanently, Harry would still be carrying Snape’s looks genes. But yet Harry’s son Albus Potter has James Potter’s messy hair and facecut. Noone had a reason to charm Albus Potter’s face. And of course, none of Harry’s kids had a hooknose or greasy hair.
And another thing, Harry had James Potter’s Quidditch skills and not to mention he did have at least some of of James Potter’s personality traits. And also, why on earth would Snape treat his own son like crap and complain that he was like James?
Probably not.
Granted, both Severus and James had similar colouring, but they looked quite different- and everyone always says Harry looks just like James. This could just be people seeing what they expect to see, except several of them recognize Harry because of the resemblance and not the other way around.
I disagree that Harry's personality has much to do with determining parentage, but I'd like to point out that he's described as being amazingly good at Quiddich- almost as though it's in his blood. He even plays the same position as James.
A case could be made for it. It's just pretty unlikely within the canon. It's also an interesting concept to play around with.
That type of content remains in the wild world of FanFiction. This particular question relates to Severitus (trope). Fanon, definitely not canon.
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