Prefect

"Only prats become prefects."

- Fred Weasley

A prefect at Hogwarts School of Witchcraft and Wizardry is a student who has been given extra authority and responsibilities by the Head of House and Headmaster or headmistress. One male and one female student are chosen from each house in their fifth year to act as prefects, and would continue to be prefects in their sixth, and seventh years until they graduate. Thus, there are approximately six prefects per house, and twenty-four prefects in the whole school at one time. The Head Boy and Head Girl may be chosen from among this number and may not be replaced.

Role
"I don't believe it! I don't believe it! Oh, Ron, how wonderful! A prefect! That's everyone in the family!"

- Molly Weasley

Prefects are allowed to take House points away from other students as penalty for breaking rules, but they are not allowed to take points from other prefects. They also patrol hallways to ensure that other students are not breaking curfew. There is a bathroom with a large, pool-like bath on the fifth floor of Hogwarts castle that is reserved for prefects. The only known password to this bathroom is "pine fresh." They also take the first years to their dormitories on their first day of school.

Once a student becomes a prefect, they have a better chance of becoming Head Boy or Head Girl; however, a student is not required to have been a prefect to become Head Boy or Head Girl. This fact was exemplified in the knowledge that Remus Lupin was a Gryffindor prefect but James Potter was later appointed the Head Boy.

Prefects are given a badge; the colours are the colours of the prefect's House. They're supposed to wear the badge on their school uniform. The badge would have the letter 'P' on it while the Head Boy's badge would have 'HB' on it, and the Head Girl's with 'HG'. If the prefect is in his or her house Quidditch Team, he or she would not be required to wear the prefect badge on the Quidditch Robes.

Hufflepuff

 * Cedric Diggory
 * Ernie Macmillan
 * Hannah Abbott

Gryffindor

 * Albus Dumbledore
 * Remus Lupin
 * Bill Weasley
 * Charlie Weasley
 * Percy Weasley
 * Ron Weasley
 * Hermione Granger

Ravenclaw

 * Penelope Clearwater
 * Anthony Goldstein
 * Padma Patil

Slytherin

 * Tom Riddle
 * Lucius Malfoy
 * Draco Malfoy
 * Pansy Parkinson

Hermione Granger was a sensible prefect, and took the role very seriously, Ron Weasley was a little less serious about it, in fact he was extremely surprised to be chosen as a prefect as he expected Dumbledore would have chosen Harry but Dumbledore thought Harry would have too much on his mind and gave it to Ron. Draco Malfoy and Pansy Parkinson abused their positions greatly, to the annoyance of Hermione Granger.

Behind the scenes

 * There was some confusion about the point-taking ability of prefects after the original release of Harry Potter and the Order of the Phoenix. It had previously been stated in Harry Potter and the Chamber of Secrets that prefects could dock points, but in a scene in the first printing of Order of the Phoenix Ron Weasley, Ernie Macmillan, and Draco Malfoy all either state outright or imply that prefects are not allowed to take points. This was pointed out as a mistake, and subsequent printings had a slightly different version of the dialogue, making it clear that prefects can take points, just not from other prefects.
 * Quidditch captains are given the same rights as the prefects like the password to the Prefect's Bathroom, but are not allowed to dock points.
 * At any given time, there are 24 prefects at Hogwarts School of Witchcraft and Wizardry.