Background::Previous studies have reported associations of specific maternal and paternal lifestyle factors with offspring’s cognitive development during early childhood. This study aimed to investigate the prospective associations between overall parental lifestyle and offspring’s cognitive performance during adolescence and young adulthood in China.Methods::We included 2531 adolescents aged 10-15 years at baseline in 2010 from the China Family Panel Studies. A healthy parental lifestyle score (ranged 0-5) was constructed based on the following five modifiable lifestyle factors: Smoking, drinking, exercise, sleep, and diet. Generalized estimating equation models were used to examine the association between baseline parental healthy lifestyle scores and offspring’s fluid and crystallized intelligence in subsequent years (2012, 2014, 2016, and 2018).Results::Offspring in the top tertile of parental healthy lifestyle scores performed better in overall fluid intelligence (multivariable-adjusted β = 0.53, 95% confidence interval [CI]: 0.29-0.77) and overall crystallized intelligence (multivariable-adjusted β = 0.35, 95% CI: 0.16-0.54) than those in the bottom tertile of parental healthy lifestyle scores. The results were similar after further adjustment for the offspring’s healthy lifestyle scores and persisted across the subgroups of parental socioeconomic status. Additionally, maternal and paternal healthy lifestyle scores were independently associated with better offspring’s cognitive performance, with significant contribution observed for paternal never-smoking, weekly exercise, and diversified diet. When both parents and offspring adhered to a healthier lifestyle, we observed the highest level of the offspring’s overall crystallized intelligence. Conclusions::Our study indicates that parental adherence to a healthier lifestyle is associated with significantly better offspring’s cognitive performance during adolescence and early adulthood, regardless of socioeconomic status. These findings highlight the potential cognitive benefits of promoting healthy lifestyles among parents of adolescents.