Household food waste is one of the major obstacles to meeting global emission targets. Yet, it seems that we still do not fully understand why some people are more driven than others in their engagement to reduce household food waste. Here, we take a new perspective and examine (a) the perceived morality of food waste as a driver for food waste behavior and (b) whether interventions that associate food waste with either the moral foundation of harm or disgust can increase both intentions to reduce food waste and to engage more in future meal planning. Across two study phases (N = 698 and 446; respectively), we found support for our hypothesis that the belief that food waste is morally wrong is negatively associated with self-reported food waste. Moreover, we found that a harm manipulation, relative to a disgust manipulation and a control condition, increased participants’ intention to reduce food waste and future meal planning intentions via food waste moral judgment, but only for those individuals who were at mean or higher values on the care foundation. A disgust manipulation, in contrast, compared to a harm manipulation, directly elicited stronger intentions to reduce food waste and to plan meals, but again only for those who endorsed the associated purity foundation. Our findings suggest different cognitive mechanisms for individuals who ground their morality in the care and the purity foundations and thus have several implications for practice and future research.