Nanoparticle (NP) applications are growing worldwide, influencing diverse aspects of daily life. Nanotechnologies are presented as disruptive innovations with the potential to solve unsolvable situations. From self-cleaning construction materials and environmental remediation systems to advancements in the textile and cosmetics industries, the impact of these technologies is widespread. However, the most remarkable progress has been made in nanotechnological applications for biomedicine. Novel NP applications have been developed for both in vivo and in vitro diagnostics, drug delivery systems, and revolutionary oncological treatments. In the field of reproductive medicine, the development of NP-based applications has also seen significant growth, particularly in improving assisted reproductive technologies (ART). Systems based on NP functionalization with specific biomarkers for the selection of high-quality spermatozoa have gained considerable importance and are now routinely used in human fertility clinics. Despite these advances, the development and application of nanotechnology for oocytes and embryos have been more limited. Some progress has been made in improving maturation rates by adding NP to in vitro culture media, and post-thaw development rates have shown improvement through the incorporation of NP during a vitrification process. Moreover, a system for labeling and identifying oocytes and embryos based on NP has been introduced. Recently, a novel NP-based tool has been developed for handling oocytes and embryos, showing promising results for its application in ART. This chapter covers the ultimate applications, developments, and concerns surrounding the use of nanotechnologies in ART.