Though there are many themes in Paper Towns that many teens can relate to, such as friendship, dissatisfaction, and perseverance, the most commonly identified and most prevalent is the theme of identity.
The importance of the theme of identity in Paper Towns is not only limited to personal identity, but also includes how people perceive the identity of others as well. The two protagonist characters go on a journey to discover their own identities, and end up with shifting perceptions of the other people in their lives. This story illustrates how many people view themselves and others through their own personal lenses, which creates two-dimensional (or "paper") views of what are, in reality, much more complex entities. An example of this is how, throughout the story, each character expresses a different interpretation of who the female protagonist really is, including the character herself. By comparison, the male protagonist, who initially had an idolized perception of the female protagonist, begins to see her in a more realistic manner and comes to the realization that she isn't the person he thought she was at all. He also gains a more realistic view of his other friends, and comes to appreciate them more deeply.