The sensitivity of tree growth to external climatic factors varies with tree age; however, most previous studies have primarily focused on natural forest species, while comparable investigations on plantation species remain limited, especially in China's sandy lands. In this study, we developed ring-width chronologies for four age classes-young, middle-aged, mature, and overmature-of Simon poplar (Populus simonii Carr.) plantations located in a representative distribution area of the Ordos Plateau, northern China. our objective was to quantify the age-dependent sensitivity of radial growth to climatic variability for Simon poplar plantations. The results indicated that the statistical quality of the Simon poplar chronologies exhibited a consistent improvement with increasing stand age: chronologies from younger stands displayed lower statistical quality, whereas those from older stands demonstrated higher statistical quality. The climate-growth relationship of Simon poplar chronologies showed a distinct age-related pattern, characterized by a progressive increase in sensitivity from young to mature stands, followed by a decline in old stands. These findings enhance our understanding of age-dependent variations in climatic sensitivity and provide empirical evidence to evaluate the temporal stability of growth-climate relationships in plantation forests of northern China under climate warming.