<p>Liquid jets at the micro and nanoscale are finding wide applicability in modern science and technology concerning combustion, cooling, biomedicine, energy, and printing. This review is intended to present a brief overview of the evolution of jet studies and the systematic development of approaches to understanding jet dynamics. It focuses on the effects of diverse parameters—mainly fluid properties, nozzle specifications, and molecular energy—on jet behavior and stability at the microscale, and especially at the nanoscale regime. A wide variety of conventional methods, like linear stability theory, nonlinear stability theory, and energy method, are incorporated to understand the flow instability and the breakup, along with their applicability for jets at micro and nanoscales, are reviewed. At the micro- or nanoscale, surface forces dominate over volumetric forces and this can be strategically utilized to achieve high efficiency in heat transfer for microelectronic chip cooling, inkjet printing, high-resolution charge printing, and biomotor development. However, these advantages also introduce greater complexities, necessitating precise experimental and numerical methods for study. Moreover, transitioning towards the nanoscale introduces molecular interactions that can significantly impact system dynamics, thereby increasing the complexity of the overall physics. This review endeavours to delineate a comprehensive guideline aimed at facilitating future research encompassing computational, experimental, and theoretical methodologies for investigating the dynamics of micro and nanojet behaviours. By synthesizing insights from diverse domains, this effort aims to provide a roadmap that elucidates the intricacies of these phenomena and their prospective applications in the future.</p> Graphical abstract <p></p>