["Family Relations, EarlyView. ", "\nABSTRACT\n\nObjective\nThis study examines how subjective expectations of upward class mobility influence fertility intentions in China and investigates the underlying mechanisms and heterogeneity of this effect.\n\n\nBackground\nIn the context of China's persistently low fertility rates, understanding sociopsychological factors beyond policy is crucial. This study shifts the focus from actual social mobility to the role of subjective mobility expectations—individuals' beliefs about their future socioeconomic status—in shaping fertility decisions.\n\n\nMethod\nUsing 2021 China General Social Survey (CGSS2021) data, an ordered probit model was employed to analyze the relationship. Robustness checks and the Karlson–Holm–Breen method for mediation analysis are conducted. Heterogeneity is examined across regions, residence types, and individual demographics.\n\n\nResults\nUpward class mobility expectations significantly increase fertility intentions, particularly for having multiple children. This effect is mediated by enhanced social trust, increased investment behavior, and greater happiness. The impact is stronger in eastern/central regions and among urban residents and is more pronounced for highly educated individuals, males, and those working outside the public sector.\n\n\nConclusions\nOptimistic expectations of upward mobility are a significant positive predictor of fertility intentions, operating through improved psychosocial and economic outlooks. The effect varies substantially across different societal groups.\n\n\nImplications\nPolicy should focus on creating credible pathways for upward mobility, such as strengthening education and lifelong learning, to boost fertility intentions. Support policies should target non–public sector employees, and regional development strategies should aim to reduce disparities in mobility opportunities.\n\n"]