Arguably, active travel (AT) is important for active aging. Using data from the Travel Survey of Xiamen Residents 2015 and geodata, this study develops a set of multilevel regression models to scrutinize the effect of the neighborhood-level built environment on three AT outcomes (daily AT propensity, frequency, and time) of older adults aged 60 years or above in Xiamen, China. Its results show that the built environment truly shapes the AT behavior of older adults. Land use mix, intersection density, and bus route density have a positive association with AT, whereas the distance to the commercial center has a negative association. Population density has no significant association with the AT behavior of older adults. Land use mix is the most significant built-environment variable. Various robustness checks confirm the plausibility of the key findings. This study provides practical implications for China's national strategy of "actively addressing population aging."1.