Who is the antagonist in "Because of Winn-Dixie?"
I do not think that there is any one person who is an antagonist throughout the whole book. An antagonist is a character who works against the main character and tends to thwart her. Opal is clearly the protagonist, so who fits the bill as her antagonist?
Sometimes it is her father, who will not give her the information she wants about her mother. I would say that he is a major antagonist in the book.
I guess you could say it's the Dewberry boys, but I think they're more of a minor annoyance than a real antagonist.
So I guess I'd say that if it's a person in the book, it's her father. Otherwise, her antagonist might really just be her circumstances since her main conflict is really against her loneliness.
In the book "Because of Winn Dixie" the antagonist is really unseen. You could say preacher was an antagonist at first because he did not want Winn Dixie to be Opal's dog. Opal had found the dog in the grocery store and brought him home. Her father saw the dog as nothing but trouble. Eventually, Win Dixie was able to lure her way into the heart of preacher and the town's people.
There are many difficult circumstances in the book. The woman that people call the witch is really lonely and needs the love that Winn Dixie and Opal bring to her. Opal needs to find a way to fill the emptiness left behind because of her mother's death. Winn Dixie also helps Opal to make new friends.