What is the theme in Joy in the Morning by Betty Smith?

Coming of age is the main theme. This novel, foremost, tells the story of Annie Brown's journey from childhood to adulthood. She leaves childhood behind when she, against her mother's wishes, moves away to marry Carl Brown, her childhood sweetheart.

The novel, to a lesser extent, tells the coming of age story of Carl, who goes from a single college sophomore to a husband, father and lawyer in two years. He steps up to provide for his family while pursuing his dreams to become a lawyer.