Background: Active attitude toward treatment and health (ATH) leads to improved cooperation and better health outcomes in patients. Supporting it in the population of older adults is a growing need in primary care. Recognising the role of gender, health and other sociodemographic factors can help to distinguish patients who need the most assistance in activation from general practitioners (GPs). The objective of the study was to investigate gender differences in ATH as well as the moderating role of self-assessed health (SAH) and selected sociodemographic factors (age, education, financial status, marital status). Methods: A cross-sectional, multicentre study among 4936 primary care older patients (aged 50+) was conducted. The PRACTA-Attitude toward Treatment and Health questionnaire (PRACTA-ATH) was used to measure the cognitive, emotional (positive and negative affect), and motivational dimensions of ATH. Patients were approached before and after their visits in the primary health-care facilities randomly selected in Central Poland. Results: Generalised linear models (GENLIN) revealed the main effects of gender, SAH, and sociodemographic characteristics, such as financial status, marital status and education. Interaction effects of gender and age (Wald’s χ2 = 24.767, p