In the book version of Goblet of Fire, Rita Skeeter is an unregistered Animagus, who can turn into a beetle to eavesdrop on Harry and his friends. This is completely unmentioned in the movie.

In the movie version of Goblet of Fire, Neville gives Harry the gillyweed for the underwater task in the Triwizard Tournament. In the book, however, it is Dobby who steals the gillyweed from Professor Snape's cupboard and gives it to Harry.

Throughout the books, there are several mentions of Harry having green eyes, just like his mother, Lily. In the movies, Harry's eyes were blue because Daniel Radcliffe (who has blue eyes) was allergic to the contact lenses that would have changed his eye color to green.

Sadly, this charming scene from the book, Harry Potter and the Prisoner of Azkaban, never made it into the film. "Ron Weasley, who was one of Harry's best friends at Hogwarts, came from a whole family of wizards. This meant that he knew a lot of things Harry didn't, but had never used a telephone before. Most unluckily, it had been Uncle Vernon who had answered the call. 'Vernon Dursley speaking.' Harry, who happened to be in the room at the time, froze as he heard Ron's voice answer. 'HELLO? HELLO? CAN YOU HEAR ME? I — WANT — TO — TALK — TO — HARRY — POTTER!'"

In the Chamber of Secrets book, Mr. Weasley fixes Harry's broken glasses with magic, but in the film, Hermione uses magic to fix them while they are in Diagon Alley buying their school supplies.

While the fact that Harry gave Fred and George their startup money for Weasley's Wizard Wheezes is referenced in later films, the scene in Goblet of Fire where Harry actually gives them his winnings only happens in the book.

In the movie version of Prisoner of Azkaban, it's made clear that the Firebolt is a gift from Sirius.

This conversation between Professor Slughorn and Harry in the Half-Blood Prince film never happens in the book.

In the Deathly Hallows book, Harry uses the Elder Wand to mend his own broken wand, and then plans to return the wand to Dumbledore's tomb. In the movie (Deathly Hallows Part Two), Harry breaks the Elder Wand in two.

In Harry Potter and the Half-Blood Prince, we see Harry mention spotting the diadem — although at the time, he had no idea what it was — when hiding his potions book in the Room of Requirement.

Cho Chang tells Umbridge about Dumbldore's Army in the film version of The Order of the Phoenix, but in the book, it's her friend Marietta Edgecombe who tells.

In the book, the story is told by Professor Binns.

In the books, Hermione is described as having "lots of bushy brown hair, and rather large front teeth." In the movies, there is no mention of her having notably large teeth.

This scene is notably absent from the movie.

In The Half-Blood Prince book, we get an in-depth introduction to and description of Voldermort's family history. There is no mention of this backstory in the movies.

Sadly, this touching scene from Goblet of Fire never made it into the film: "Mrs Weasley set the potion down on the bedside cabinet, bent down, and put her arms around Harry. He had no memory of ever being hugged like this, as though by a mother."

This charming scene from the Deathly Hallows Part One film does not happen at all in the book.

While this VERY IMPORTANT scene from Deathly Hallows was absent from the film, it does appear as a bonus deleted scene in the DVD extras for Harry Potter and the Deathly Hallows, Part One

In the movie version of Prisoner of Azkaban, Draco and friends do make fun of Harry, but they don't go all out and dress up in Dementor robes to scare Harry off his broom during the Quidditch match.

This scene from the very first book never happens in the movie.