As an important environmental factor, light has a substantial effect on plant seedling growth. The amount of light changes considerably during forest successions or micro-successions in mature forests, and therefore, it is necessary to evaluate the effects of light on the growth of woody plant seedlings of different life forms. Although much recent research has been conducted to determine shade tolerance of woody plants, most of these studies focused only on one or two plant species, and review studies across experiments are needed to elucidate plant responses to light conditions. In this meta-analysis, we collected data from experimental studies on growth responses of woody plants to shading gradients. Consequently, 106 species belonging to 42 families from 71 published papers (to 2016) were collected. Extracting data from these studies, we conducted a meta-analysis by using MetaWin 2.1 software. The growth responses of woody plant seedlings were analyzed using the mean values of seedling height, basal diameter, biomass, and height:basal area ratio in the treatments relative to those of the control (with full light) to estimate the appropriate effect size for the analysis. Our results showed that (1) Compared with seedling height, basal diameter of plant seedlings was more sensitive to shade treatments, resulting in higher height:basal area ratio for seedlings growing under shade treatments; (2) Shrub seedlings exhibited stronger tolerance to shade treatments than did tree seedlings; (3) Regarding life forms with different leaf traits, basal diameters of deciduous broadleaved and evergreen broadleaved species were significantly inhibited by shading of 0-20% and 20%-40% light intensity of unshading control, whereas the basal diameter of evergreen conifers was relatively insensitive to shade treatments; (4) The height:basal area ratios of deciduous broadleaved and evergreen broadleaved plants were significantly enhanced by shading treatments, whereas the height:basal area ratio of evergreen conifers were relatively insensitive to shading treatments, which indicated that light responses of plant seedlings may strongly depend on the leaf traits of the species. Our results increased our understanding of how seedling growth responds to different light conditions in natural forests.