International research on long-term care (LTC) can valuably inform LTC policy and practice, but limited transnational collection of data on key LTC issues restricts the contributions of international LTC research. This special collection of Gerontology and Geriatric Medicine helps close the gap between the status quo and the potential for international LTC research by cultivating a transnational common ground of internationally prioritized measurement concepts and sowing the seeds of international LTC common data elements. The articles in this special collection address both adaptive and technical challenges to international LTC measurement, build on and complement existing LTC measurement systems, and provide diverse international perspectives on the measurement of LTC across four overarching domains: LTC contexts, workforce and staffing, person-centered care, and care outcomes. From large transnational teams of scholars specifying the meanings of central LTC concepts, to smaller subnational research teams testing new measures of person-centered care across diverse local LTC settings, contributors spark new insights and point in new directions for a LTC measurement infrastructure supportive of person-centered care and lifelong thriving.