-Negotiations between engineering and non-engineering perspectives are central in humanitarian engineering and learning through service initiatives, and these negotiations inevitably include dimensions of social justice. But what frameworks guide engineers through such negotiations? To date, in published scholarship, social justice has played little to no role in providing structure for work in humanitarian engineering and learning through service. Yet structure is needed to think and act systematically on the social justice dimensions inherent in humanitarian engineering and learning through service initiatives and practices. Drawing from multiple data sources, including interviews with engineering education faculty on the barriers and opportunities to integrating social justice dimensions in such initiatives, we provide a social justice definition and criteria that serve as flexible guidelines for humanitarian engineering and learning through service initiatives. Grounded in a synthesized definition of social justice, the social justice criteria can guide engineers to recognize and map human and non-human, engineering and non-engineering components in problem definition and solution-with social justice at the core. Along with other benefits, these criteria can act as a foundation from which to launch, evaluate, and improve on humanitarian engineering and learning through service work, serving as a vehicle for project initiation, reflection, and self-critique.Index Terms -humanitarian engineering, learning through service, social justice criteria, social justice applications.With great power, comes great responsibility. Engineering has the power to transform the world: the water we drink, air we breath, infrastructure we use for energy and transport, medicines we use for healing, way we conduct warfare and peace, and much, much more. Given the power of engineering, we need an engineering education that is tailored to the great responsibility engineers will assume in transforming life in the 21st century and beyond. Engineers design, build and operate simple and complex systems, capable of affecting the lives of millions of people, as well as the allocation of resources (e.g., water), opportunities (e.g., access to work and commerce), risks and harms (e.g., flooding), and how diverse social groups receive these differently. Consider the devastation that took place in New Orleans in 2005. When the levees-an engineered infrastructure system-failed, one can see that when a natural hazard, like Hurricane Katrina, interacts with engineered systems on which people's lives depend, the consequences are different for different groups of people. In the case of Katrina, the failure of the levees in New Orleans affected the poor (mostly black) and those with disabilities more than any other social groups, taking away their resources (e.g., property), opportunities (e.g., to rest and replenish at home so one can be a functional member of society) while exposing them to more risks and harms (e.g., disease, drowning, ...