Objective: The aim of this study was to evaluate the prevalence of anticipatory grief (AG) and investigate the relationship between AG, anxiety, depression, adult separation anxiety, and attachment styles in a sample of lung cancer patients. Understanding these interactions may lead to improved psychological support for terminal cancer patients. Methods: 65 participants completed a sociodemographic data form, and their cancer diagnosis characteristics were evaluated. Patients were assessed using the Prolonged Grief Disorder Scale-Patient Form (PG-12-P), the Hospital Anxiety and Depression Scale (HADS), the Relationship Scales Questionnaire (RSQ), and the Adult Separation Anxiety Questionnaire (ASA). Participants with probable AG according to the PG-12-P were included in a clinical interview. Results: 16 participants (24.6%) were diagnosed with probable AG. Correlation analyses revealed a positive relationship between probable AG and age, HADS scores, and ASA scores. Logistic regression analysis indicated significant relationships between probable AG, age, and HADS scores. The relationship between probable AG and ASA scores lost its significance in the logistic regression analysis. Conclusion: The findings suggest a significant relationship between AG and age, as well as AG and depression and anxiety scores. This research contributes to the understanding of AG, which is still being conceptualized, and highlights the potential link between AG and adult separation anxiety, suggesting the need for further research with larger sample sizes.