This study explores the influence of hostile media perception (HMP) and other antecedents to mothers’ willingness to speak up regarding the issue of breastfeeding, particularly in online environments. An online survey of mothers (N = 455) revealed that mothers are more likely to express opinions about breastfeeding online, and also with friends and family, if they consider media coverage of the issue biased or hostile. In addition, as hypothesized, the personality trait of outspokenness influences mothers’ willingness to speak up and mediates the effect of HMP on communication, although there were conditional effects based on mothers’ past breastfeeding behaviors. Implications are discussed.