The future of agricultural production, particularly of food products, depends on innovations that increase agricultural output within the constraints of limited available land. These innovations must simultaneously enhance crop quality and minimize the negative impacts of agricultural practices on the environment, biodiversity, and human and animal health. Nanotechnology offers a wide range of opportunities to develop novel agricultural tools, either through the use of nanoparticles alone or in combination with bio-based active components that enhance plant nutrition, growth, and quality. Nanobiofertilizers and nanobiopesticides—sourced from plants or microorganisms or formulated by integrating bio-based components with nanomaterials—have demonstrated significant influence on plant interactions with their environment, including both biotic and abiotic factors, resulting in improved agricultural productivity. This chapter aims to summarize the main mechanisms by which nanoscale solutions interact with plants and surrounding microbial communities, particularly soil microbiota, which collectively contribute to strengthening beneficial (i.e., symbiotic) plant–microbe relationships, supporting improved plant growth, yield, and soil health. While many potential interactions between nanomaterials and living systems, especially long-term effects, remain poorly understood, this chapter provides an overview of the documented benefits of nanomaterial applications in plant production with an emphasis on microbially mediated mechanisms of plant growth promotion.