Only one study to date has experimentally demonstrated the existence of formula feeding stigma, negative attitudes towards mothers who formula feed rather than breastfeed. That study found evidence for the existence of formula feeding stigma and attributed its cause to perceived intentionality. That is, when researchers exposed participants to an Instagram post, allegedly written by a formula feeding mother, the participants rated the mother more negatively if she had always intended to formula feed than if she had not originally intended to formula feed. In the current study, we utilized a factorial design to explore whether the expressed stigma was truly a function of perceived intentionally or if perceived controllability was the more important factor. Participants were randomly assigned to view one of four social media posts about how a mother came to formula feed. In the posts, the mother formula fed for either a controllable reason (i.e., convenience) or an uncontrollable reason (i.e., surgery) and the decision was either intentional (i.e., she had always planned to formula feed) or unintentional (i.e., she had originally planned to breastfeed). Then they responded to questions measuring stigmatizing beliefs about the mother. Results indicated that when the mother reported formula feeding for a controllable reason she was rated less positively than when the mother reported formula feeding for an uncontrollable reason. As predicted, intentionality did not influence levels of formula feeding stigma. Therefore, when controllability is parsed out from intentionality, controllability is the more important factor in formula feeding stigma.