As most of the literate and cinema-going world now knows, Harry Potter and Hermione Granger are two of the main characters in J.K. Rowling's Harry Potter series of fantasy novels, the first of which is Harry Potter and the Sorcerer's Stone.

As for similarities, Harry Potter and Hermione Granger are both about the same age and become first-year students at Hogwarts School of Witchcraft and Wizardry at the same time. The sorting hat assigns them both to the house of Gryffindor, where they both become best friends with each other and Ronald Weasley after an encounter with a troll during which Harry and Ronald save Hermione. Harry and Hermione go to the same classes, share many adventures, oppose bullies, and fight the evil Lord Voldemort and his minions.

One of the significant differences between Harry and Hermione is that Harry Potter's real parents are a witch and a wizard, whereas Hermione is muggle-born, which means that her parents were normal humans and she is the first witch in their family. Another difference is that Hermione is studious and precocious, able to study hard and learn spells quickly, but Harry has a normal aptitude for academics, sometimes struggling with his lessons. It's often Hermione who has to come up with appropriate potions or spells, as she has read so many books and has an innate understanding of them. Additionally, Harry is an orphan, his parents having been killed by Voldemort, while Hermione's parents are still alive.

Hermione and Harry share certain qualities that eventually lead to their making friends with each other: some examples include academic aptitude and a particular gift for magic, as well as important personal qualities like loyalty to friends and bravery in the face of danger. As well, they are both members of the Gryffindor house, and they both feel sensitive about anything to do with their parentage.

The differences in their characters, however, are also interesting: Harry Potter's parents were both students at Hogwarts themselves, while Hermione's parents are both muggles and dentists. Harry's parents are both dead, which has a serious impact on Harry, making him vulnerable to anything to do with the memory of his parents, while Hermione's parents are both living, and Hermione is rather sensitive to the fact that she is muggle-born. As well, Harry's approach to studying is more haphazard than Hermione's, who loves going to the library and researching.