Semiconductor nanowires (NWs) have been investigated for decades, but their application into commercial products is still difficult to achieve, with triggering causes related to the fabrication cost and structure complexity. Dopant control at the nanoscale greatly narrows their exploitation as components for device integration. In this context, doping appears the truly last missing piece of the puzzle for III–V NWs, for them to become commercially exploitable. In this paper, we review the doping of bottom up III–V NW arrays grown by molecular beam epitaxy and metal-organic vapor phase epitaxy, aiming to link materials science challenges with the critical aspect of device design. First, the doping methods and mechanisms are described, highlighting the differences between self-assembled and ordered NW arrays. Then, a brief overview of the available tools for investigating the doping is offered to understand the common strategies used for doping characterization. Both aspects are crucial to discuss the recent advancements in reproducibility and up-scalability, which are discussed in view of large area fabrication for industrial production. Finally, the most common doping-related challenges are presented together with the latest solutions to achieve high performing NW-based devices. On this basis, we believe that new insights and innovative findings discussed herein will open the low dimensional materials era, on the premise of multidisciplinary collaborative works of all the sectors involved in the design and optimization of commercial products.