I would confirm for you that the characters listed by the student above are the most important characters in the book for various reasons.
Scout, whose real name is Jean Louise, narrates the story for us from a 6-year-old girl's point of view.
Atticus is her father. He is a lawyer and a state legislator. The kids call him by his first name which seems a little odd. But, maybe there is a considerable respect that hinges with that too. Watch for it as you read.
Jem is Scout's older brother who like most normal older brothers looks for ways to torment her. The story will reveal their relationship is solid and they trust each other completely.
Boo is a neighbor that draws their attention because he doesn't leave his house. The town offers great rumors about his private existence. For the majority of the book, Boo seems unimportant, but the story hinges on his presence.
Tom doesn't seem important in the beginning. He is a man that Atticus will defend in a court case. The town reacts and gets completely involved in this case.
This book teaches great values for a society and watching each of these characters from their perspectives will teach you quite a bit. Happy reading!
Actually there are a lot of main characters. If you notice, the book is broken down into two parts. In each part there are main characters. So if you are talking about the whole novel, you would have way more than five characters.
The main characters are Scout, Jem, Atticus Boo Radley,Tom Robinson. there are other main characters but those are the main ones