Changes in science funders’ mandates have resulted in advances in open access to data, software, and publications. Research capacity, however, is still unequally distributed worldwide, hindering the impact of these efforts. We argue that to achieve the Sustainable Development Goals (SDGs), open science policies must shift focus from products to processes and infrastructure, including access to open source scientific equipment. This article discusses how conventional, black box, proprietary approaches to science hardware reinforce inequalities in science and slow down innovation everywhere, while also representing a threat to research capacity strengthening efforts. We offer science funders three policy recommendations to promote open science hardware for research capacity strengthening: a) incorporating open hardware into existing open science mandates, b) incentivizing demand through technology transfer and procurement mechanisms, c) promoting the adoption of open hardware in national and regional service centers. We expect this agenda to foster capacity building towards enabling the more equitable and efficient science needed to achieve the SDGs.