Students' perceived social support from important others may be an important protective factor in science self-handicapping. This study examined the extent to which science self-handicapping mediates the relationship between perceived social support and science academic outcomes (engagement and achievement). The study used a cross-sectional survey design with self-report data from 2654 participants in elementary schools and 2781 participants in high school from China. The results indicated that (1) perceived social support had an effect on students' science academic engagement and achievement; (2) self-handicapping in science mediated the entire process; (3) at different stages, different social support would not be equally important for the effects of adolescents' self-handicapping in science. The findings indicate that social support can create a positive academic environment to weaken the effect of self-handicapping on students' science academic outcomes, and educators need to consider the entire influence process differently in different academic stages of their students.