Social comparisons on social networking sites can be problematic for some individuals. However, this has never been examined in a parenting context, where the pressure for mothers to portray themselves as "perfect parents" may be high. The aim of the current study was to examine associations between making social comparisons on social networking sites With mothers' parenting, mental health, and romantic relationship outcomes. In the iMom Project, 721 mothers completed a number of questionnaires regarding their social media use, parenting behaviors, and health outcomes. Results revealed that making social comparisons on social networking sites was related to parenting outcomes (in the form of higher levels of parental role overload, and lower levels of parental competence and perceived social support), relationship outcomes (in the form of more conflict over social networking sites and perceiving less positive coparenting relationships) and higher levels of maternal depression. This study adds to a growing literature suggesting that making social comparisons online may be associated with a number of negative outcomes, and extends it to the context of mothering. This study has implications for the way that mothers use social media, specifically in the use of social comparisons. (C) 2016 Elsevier Ltd. All rights reserved.