The protagonist of Tears of a Tiger is the main character, Andy Jackson. He is a flawed person, having killed his friend and fellow basketball teammate by driving drunk, but he is still the protagonist because the reader witnesses his attempts to live with the immense guilt he carries from the accident. The antagonists are most of the adults in the novel. While Dr. Carrothers, the psychologist, tries to help Andy, he is largely unable to do so, and Andy winds up committing suicide. Before he dies, Andy feels that his teachers discredit the academic efforts of African-American students, making Andy feel like it is pointless to try hard in school. In addition, Andy feels like his parents do not connect with him because his father is too busy working to attend Andy's basketball games, and his mother does not want to attend the games. Andy feels abandoned by most of the adults in his life, so they are antagonists of this novel.
I would argue that Andy is both protagonist and antagonist in this novel. Tears of a Tiger is truly an example of man versus self conflict. Andy struggles throughout the novel to resolve his feelings concerning his role in Robbie's death. One of the truly telling moments in the novel is when Andy's English class has the discussion concerning culpability and guilt, murder and suicide, in Macbeth. Ultimately unable to come to terms with his emotion and overwhelming feelings of loss and guilt over his friend's death, Andy Jackson chooses to end his own life.