Reducing food waste is globally considered as a key challenge in developing sustainable food systems. Although most food waste is generated at the household level, consumers hardly recognize their responsibility, and the factors underpinning their perception of the quantity of food wasted at home are still unclear. This paper aims to fill this gap by analyzing the results of a large-scale survey conducted in Italy. The perceived quantity of household food waste was measured through a Likert scale and analyzed by means of a logistic regression against a set of predictors, including food waste motivations, perception of the effects of food waste, and sociodemographic variables. As expected, the perceived quantity of food waste declared by respondents was very low. Among the main determinants, food shopping habits and the level of awareness about the reasons why food is wasted played a key role. In contrast, the perception of the environmental effects of food waste seemed to be less important. Differences among subsamples recruited in different areas of Italy were detected, suggesting that further studies, as well as awareness-raising policies, should also consider context-related variables.