Purpose <p>The diagnosis of metastatic cancer entails an enormous psychological, physical, and social burden, whereby affected women do not feel adequately supported. To address this issue, the Women’s Self-Help Organization Cancer (Frauenselbsthilfe Krebs e.V. FSH) has implemented an innovative peer support program based on online group meetings moderated by trained peers to positively influence psychosocial distress and quality of life of affected women. This pre-post non-randomized study aims to systematically evaluate this program.</p> Methods <p>Participants were asked to evaluate the program in terms of expectations and concerns regarding the program, as well as experienced benefits and difficulties. We measured various psychosocial outcomes including psychosocial distress and quality of life at baseline (T0) before the program and after 6 months (T1) follow-up.</p> Results <p>We included <i>n</i> = 97 patients (mostly metastatic breast cancer) at T0 and <i>n</i> = 44 patients with matching complete data sets at T1. The results showed that the program met the participants’ expectations. The online meetings were rated as helpful in terms of sharing experiences and feeling less alone. While participants initially expressed concern about confronting others’ fates (T0), this worry diminished after participation (T1). With respect to the identification of potential effects, we found a significant reduction in psychosocial stress (<i>t</i> (43) = 3.41, <i>p</i> = .001), whereas the levels of depression and anxiety remained unchanged.</p> Conclusion <p>This online support program showed substantial benefits for the participants. For the next step, a controlled study should be performed to prove the effectiveness of this online program.</p>