Recent advances in nanoparticle (NP)technology have revealed potential to improve efficiencies in agriculture and plant biotechnology - specifically through controlled nutrient delivery, pathogen mitigation, and genetic engineering. However, most NP-based biotechnology applications have focused on demonstrative experimental studies, with few rigorous mechanistic explanations of how NPs translocate within plant structures. This article highlights advances in understanding NP transport in plants, categorized into NP movement across three length scales each distinguished by a different transport barrier: (i)the macroscale where different plant organs present unique obstacles to continuum transport, (ii)the microscale where the cell wall and dynamic size exclusion controls transport, and (iii)the molecular scale where cell and organelle membranes provide a hydrophobic barrier. To fully understand transport in plants and realize the benefits of responsible NP-based agri-technologies, researchers must combine knowledge from several disciplines and apply a multiscale approach to bridge knowledge about NP transport in plants across these length scales.