Yes, they might sound same which leads many people to confusion. But their usage is different because: They is a personal pronoun. They don't know us. They were standing there. They didn't greet me. Their is a possessive pronoun. Their house is enormous. I don't know their address. Their stories are always funny. They're is "they" + "are" written together. They're fat. They're not good at it. They're not really clever. Practice, practice, practice on Grammar Now!
