Creating innovative technologies to improve people’s lives has always been a core aim of HCI researchers and practitioners. In many cases, this impact is realized through innovations that scale to provide many people with the ability to achieve meaningful outcomes. As devices and software have become affordable and ubiquitous, our field has attempted to scale outcomes such as free access to a world-class education, on-demand personalized health interventions, and flexible employment through sharing economies. However, despite our efforts, many of these outcomes have failed to scale deeply and equitably. In this HCIC presentation, we will propose a working definition of scaling for HCI that addresses both the depth of the outcomes promoted by an innovation and the equity of people’s ability to achieve those outcomes. We will then present a set of scaling approaches from computer science and the social sciences and highlight areas that have been understudied thus far. We will conclude with a discussion of unresolved issues with the definition and approaches, and will invite feedback and critique from the HCIC community.