Abstract: Space weathering is an important physical and chemical process acting on the surfaces of celestial bodies. It can significantly modify the reflectance spectra of asteroids and consequently affect the interpretation of their surface compositions and evolutionary histories. Determining the space-weathering exposure ages of asteroids helps reveal how surface weathering accumulates and resets, and provides constraints and calibration for reliably inverting surface mineralogical composition. In this study, a sample of 10 near-Earth asteroids, 10 Mars-crossing asteroids, and 15 main-belt asteroids was selected. Based on visible–near-infrared reflectance spectra obtained from SMASS and SpeX data, the space-weathering exposure ages of these asteroids were derived using the Shkuratov model combined with a weathering function. The results show that the exposure ages of near-Earth asteroids range from 4.06 × 10⁴ to 1.59 × 10⁶ yr, those of Mars-crossing asteroids range from 3.20 × 10⁵ to 2.13 × 10⁶ yr, and those of main-belt asteroids are concentrated between 2.09 × 10⁵ and 2.93 × 10⁶ yr. Statistical analysis indicates that near-Earth asteroids have the lowest mean exposure age, 3.44 × 10⁵ yr, followed by Mars-crossing asteroids with a mean value of 9.83 × 10⁵ yr, whereas main-belt asteroids have the highest mean exposure age, 1.42 × 10⁶ yr. A positive correlation is observed between the semi-major axis and the space-weathering exposure age, suggesting systematic differences in the accumulation of surface weathering among silicate asteroids in different orbital environments. Although near-Earth asteroids experience stronger solar-wind irradiation than main-belt asteroids, their average exposure ages are significantly younger, indicating that resurfacing processes such as planetary encounters, micrometeoroid impacts, thermal fatigue, and regolith migration may also play important roles in controlling their surface weathering states. The space-weathering exposure ages derived in this work should be regarded as model-constrained equivalent timescales, mainly used for comparing the relative weathering degrees among different orbital classes. This study provides quantitative constraints on the surface weathering timescales and weathering–resurfacing evolution of small bodies in the Solar System.