Purpose <p>This cross-sectional study aimed to examine the level of psychosocial adjustment among young and middle-aged patients with lung cancer, explore the influencing factors of psychosocial adjustment, and identify the mediating role of resilience between stigma and psychosocial adjustment.</p> Methods <p>Between October 2022 and October 2023, data were collected using a self-designed demographic and disease‐related questionnaire, the Psychosocial Adjustment to Illness Scale–Self‐Report (PAIS‐SR), Social Impact Scale (SIS), and Connor–Davidson Resilience Scale (CD-RISC). The sample comprised 245 patients with lung cancer recruited from a tertiary grade A cancer center in southern China. To analyze the data, hierarchical multiple regression analyses were used, and the mediation Model 4 of the PROCESS macro in SPSS was implemented.</p> Results <p>Participants (42.9%) had moderate or severe psychosocial maladjustment. Financial stress, cancer stage, time since treatment completion, dyspnea, stigma, and resilience were included in the final regression model and explained 46.2% of the variance of psychosocial adjustment. The total and direct effects of stigma on psychosocial adjustment were significant, and a positive indirect effect was identified for stigma on psychosocial adjustment via resilience.</p> Conclusions <p>Stigma had a negative impact on psychosocial adjustment among young and middle-aged lung cancer patients, while resilience had a partial mediating effect on the relationship between stigma and psychosocial adjustment.</p> Implications for Cancer Survivors <p>Targeted psychosocial interventions should be developed to alleviate stigma, enhance psychological resilience, and ultimately support patients’ reintegration into society and their return to normal life.</p>