Self-assembled nanostructures of various polyphenylene dendrimers, prepared by drop casting dendrimer solutions on the surface of highly oriented pyrolytic graphite (HOPG), have been investigated by noncontact atomic force microscopy (NCAFM). Besides forming globular clusters, all the polyphenylene dendrimers studied self-assemble into micrometer long nanofibers irrespective of their cores (e.g., tetraphenylmethane, biphenyl, or azobenzene). The effect of the dendrimer generation and the degree of branching on the formation of dendrimer nanofibers is studied.