Exploiting bacterial DNA-acting enzymes and expanding their repertoire for genome engineering have been major technological and conceptual advances in molecular biology over the last decade. The CRISPR-Cas9 system offers many attractive superiorities, such as multiplexing, high precision, low cost, and simplicity compared to other strategies/systems/approaches known to date for gene editing. The efficient co-delivery of Cas9 and single guide RNA(s) into a desired cell and subsequent correct targeting of selected genomic fragment(s) are among the most critical and determining issues for CRISPR-Cas9-based genome engineering. CRISPR/Cas9 components can be transported into target cells via various delivery methods, including physical methods (such as electroporation and microinjection) as well as viral and non-viral methods. Physical and viral methods, with all their privileges, still suffer from disadvantages including induction of immune responses, cell damage, lack of high specificity, etc. We are witnessing a remarkable increase in the employment of nanomaterials as non-viral carriers for the delivery of the CRISPR/Cas9 system. Nanoparticles have so far presented numerous advantages such as ease of synthesis, high efficiency, low cost, size tunability, non-mutagenicity, non-immunogenicity, etc. with regard to the delivery of CRISPR/Cas9. Here, we will review the recent progress in the delivery of CRISPR/Cas9 system components via nanomaterials and outline future challenges. (C) 2020 Elsevier Ltd. All rights reserved.