Purpose <p>People with head and neck cancer face changes in appearance, difficulties swallowing, and communication challenges, which can limit their social functioning and impact interpersonal relationships, self-esteem, and work performance. The literature on how post-treatment changes affect social functioning remains limited. This study aims to explore the social functioning experiences of people with head and neck cancer after treatment.</p> Method <p>A qualitative research design with purposive sampling was employed to recruit head and neck cancer patients from a medical center in central Taiwan. Face-to-face in-depth interviews were conducted using semi-structured interview guides. Data were analyzed through qualitative content analysis.</p> Results <p>Twenty participants were recruited, with treatment completion ranging from 10&#xa0;months to 8&#xa0;years and 9&#xa0;months prior. Five themes were identified: (1) influence on willingness to participate in society, (2) interpersonal relationships and interaction, (3) giving back to society, (4) taking care of oneself, and (5) challenges in maintaining employment.</p> Conclusions <p>Post-treatment adjustments in behavior and communication are necessary for social reintegration. Treatment-related changes reduce patients' willingness to participate socially, but community involvement and personal adjustments help rebuild self-worth. Tailored support programs are recommended.</p>