The planet is rapidly urbanizing, the need for actionable evidence to guide the design of cities that help (not hinder) our health has never felt more urgent. One essential component of healthy city design is improving neighborhood conditions in previously disinvested areas. To ensure equitable city design, policy makers, city planners, health practitioners, and researchers are interested in understanding the complex relationship between urban change, gentrification, and population health. Yet, the causal link between gentrification and health outcomes remain unclear. Without clear and consistent gentrification measures, researchers struggle to identify populations who are exposed to gentrification, and to compare health outcomes between exposed and unexposed populations. To move the science forward, this paper summarizes the challenges related to gentrification measurement in the United States and Canada when aspiring to conduct studies to analyze causal relationships between gentrification and health. The paper concludes with a series of recommendations for studies aimed at examining both causes and consequences of gentrification and health.