The ever-increasing global population and intensifying effects of climate change have significantly strained food security worldwide. At this eleventh hour of utmost need, plant genetic engineering emerges as a critical solution, offering resilience, improved yields, and enhanced nutritional quality. However, conventional gene delivery methods such as Agrobacterium-mediated transformation, electroporation, and biolistics face multiple limitations including species-specific barriers, low efficiency, and tissue damage. In this context, nanoparticle (NP)-mediated nucleic acid delivery has gained immense attention as a transformative alternative. Due to their tunable physico-chemical properties, NPs facilitate precise, efficient, and minimally invasive delivery of genetic materials, including DNA, RNA, siRNA, and CRISPR-Cas components, across diverse plant species. Moreover, NP-mediated systems enable both transgenic and non-transgenic applications, addressing regulatory and biosafety concerns. This chapter delves into the molecular mechanisms governing NP acquisition, transport, and intracellular trafficking within plant systems, alongside recent advancements in employing various types of NPs such as gold nanoparticles (AuNPs), carbon nanotubes (CNTs), mesoporous silica nanoparticles (MSNs), and chitosan-based carriers. Special emphasis is given to NP-based delivery’s role in virus resistance, crop improvement, and sustainable agriculture. Although challenges regarding toxicity, scalability, and environmental safety remain, continued interdisciplinary research promises to position NP-mediated delivery as a cornerstone technology for next-generation plant biotechnology.