Introduction <p>Social determinants of health (SDOH) significantly influence cancer development, treatment response, and clinical outcomes. However, their integration into oncology clinical practice remains limited. In this study, the perceptions of oncology health care professionals regarding the influence of SDOH and the existing barriers to addressing them within the Spanish health care system.</p> Materials and methods <p>This cross-sectional study was conducted using a self-administered questionnaire distributed to oncology professionals in various autonomous communities in Spain. Sociodemographic variables, professional roles, perceptions of the impact of SDOH, and perceived barriers to addressing these social factors were analyzed. Descriptive and inferential statistics (chi-square test and Fisher’s exact test) were applied.</p> Results <p>A total of 258 professionals, mainly from medical oncology, nursing, and oncology pharmacies, participated in the study. More than 80% considered that SDOH influences cancer development and prognoses, and nearly 70% considered that SDOH influences treatment toxicity. Significant differences in knowledge levels were identified by professional role, with the most significant lack of knowledge noted in nursing, pharmacy, and radiophysics. The main barriers reported were time constraints, resources, specific protocols, and training in social and cultural competencies.</p> Conclusions <p>There is a high level of awareness regarding the relevance of SDOH in oncology, although knowledge gaps and structural obstacles persist. Therefore, it is imperative to develop training and institutional interventions that integrate the social component into oncology care, thereby promoting more equitable and patient-centered clinical practice.</p>