The role of social support in the online setting is explored in this study. For this purpose, the posts of infertility treatment patients participating in an infertility treatment online support group between 2002 and 2016 were retrieved. Members who contributed at least 100 words were divided into two groups according to the treatment outcome they reported (pregnancy). The association between the length of group membership, type of support provided, intensity of interaction, active support seeking, overall sentiment and the amount of sadness, anxiety and anger words and the treatment outcome was examined. The findings suggest that online social, in particular emotional, support acts as a buffer between the stressor and the treatment outcome. The expression of anger and initiating of communication by new members diminish this relationship.