It is well documented that dendrimers were described as one of the most tunable nanomaterials both for therapeutic applications and diagnostics. This concise review surveys the different types of both non-targeted and targeted drug-encapsulated dendrimers and dendrimer–drug conjugates in oncology. In addition, progress in biocompatible dendritic architectures is discussed as it relates to the development of anti-cancer agents through in vitro and in vivo studies. In particular, we present relevant examples of these nanodevices to treat aggressive cancers such as colon and brain tumors. This review concludes with a brief survey of perspectives for clinical translation.