The differential susceptibility model proposes that some children are more susceptible to both positive and negative peer relationships than others. However, experimental evidence supporting such a proposition is relatively scarce. The current experiment aimed to help address this gap, investigating whether Chinese (pre)adolescents who have higher levels of general sensitivity to the environment (i.e., higher levels of sensory processing sensitivity [SPS]) would be more strongly affected by peer acceptance and rejection. (Pre)adolescents aged 8.75–15.17 ( N = 1,207, Mage = 11.19 years, 59.7% boys) randomly received four hypothetical vignettes describing either peer acceptance or peer rejection. Before and after this manipulation, they reported on their positive and negative mood. We assessed (pre)adolescents’ SPS using (pre)adolescent self-reports, as well as caregiver reports for a subset of (pre)adolescents ( n = 480). Results supported differential susceptibility to peer rejection and acceptance for self-reported SPS, but not caregiver-reported SPS. (Pre)adolescents with higher levels of self-reported SPS not only had stronger increases in positive mood upon peer acceptance (susceptible “for better”; β = .09, p = .001) but also stronger increases in negative mood upon peer rejection (susceptible “for worse”; β = .09, p = .023). These findings illustrate the short-term dynamics that may underlie differences in children’s long-term susceptibility to acceptance or rejection by peers.