It has been demonstrated that RNA molecules-mRNA, siRNA, microRNA, and sgRNA-regulate cancer-specific genes, and therefore, RNA-based therapeutics can suppress tumor progression and metastasis by selectively upregulating and silencing these genes. However, the innate defense mechanisms (e.g., exonucleases and RNases) involving the human immune system catalyze the degradation of exogenous RNAs. Thus, nonviral nanoparticles have been employed to deliver therapeutic RNAs for effective cancer gene therapy. In this minireview, we highlight efforts in the past decade to deliver therapeutic RNAs for cancer therapy using novel nanoparticles. Specifically, we review nanoparticles, including lipid, polymer, inorganic, and biomimetic materials, which have been employed to deliver therapeutic RNAs and evoke tumor suppressing responses. Finally, we discuss the challenges and considerations that may accelerate the clinical translation of nanotechnology-mediated RNA therapy.