This paper analyzes the television show Star Trek: Deep Space Nine within the context of the other Trek series, especially the original series and Star Trek: The Next Generation, with a particular focus on multiculturalism. Previous Trek series present an image of the United Federation of Planets that has evolved into a peaceful, cooperative, post-scarcity, multicultural utopia, but gloss over the difficulties the Federation governments must have faced in creating this utopia and must still face in maintaining it. I argue that DS9’s shift in focus away from exploration and towards a postcolonial, multicultural, stationary setting allows the show to interrogate the nature of the Federation’s multicultural utopia and showcase the difficulties in living in and managing a space with a plurality of cultures. The series, much more than those that precede and follow it, both directly and indirectly criticizes the Federation and its policies, suggesting that its utopian identity is based more in assimilation than multiculturalism. Nonetheless, this criticism, which is frequently abandoned and even undermined, is inconsistent. By focusing on three of the show’s contested spaces/settings—the space station itself, the wormhole, and the demilitarized zone—I analyze the ways in which DS9’s ambivalent criticism of the success of multiculturalism challenges the confidence of the Trek tradition.