<p>Women with endometriosis often experience pain-related symptoms that negatively affect their daily lives, overall health, and well-being. This study aimed to evaluate the effects of the Endometriosis Self-Care Support Program (ESSP) on quality of life, self-care behaviors, depressive symptoms, anxiety, and stress. A randomised controlled research design was adopted. This study was conducted between May 2024 and June 2025 with 65 women with endometriosis. This phase included two groups: the intervention group (ESSP group) received the ESSP, comprising structured education and motivational interviewing based on Orem’s Self-Care Model, while the control group received standard care. The “Endometriosis Health Profile Questionnaire-5 (EHP-5)”, the “Endometriosis Self-Care Behaviors Scale (ESCBS)” and the “Depression, Anxiety and Stress Scale-21 (DASS-21)” were administered to both groups as a pre-test prior to the intervention, as a post-test immediately after the intervention (at the 1st month), and as a follow-up test three months post-intervention. In addition, data were collected using the “Participant Identification Form”. There were no statistically significant differences between the groups regarding baseline (pre-test) scores on the EHP-5, ESCBS, and the depression, anxiety, and stress subscales of the DASS-21 (<i>p</i> &gt; 0.05). Post-test and follow-up ESCBS scores were significantly higher in the ESSP group (<i>p</i> &lt; 0.05), while EHP-5 and DASS-21 depression and anxiety scores were significantly lower (<i>p</i> &lt; 0.05). No significant group differences were observed for the DASS-21 stress subscale (<i>p</i> &gt; 0.05). Women who received the ESSP had higher quality of life and greater self-care behaviors. Additionally, their levels of depression and anxiety were lower.</p>