Weight-based stigmatization is an important societal issue because it may lead to significant social exclusion that can induce stress and contribute to poor physical and mental health in people who are targeted. It may also ironically contribute to the maintenance of obesity. The present study aimed to explore sociodemographic and individual predictors of negative attitudes towards obesity in the general population of the province of Quebec. An online survey was completed by 1615 adults living in Quebec. Height and weight were self-reported to calculate body mass index (BMI). A path analysis was performed with robust estimators in order to examine predictors of three negative attitudes towards obesity, namely dislike of fat people, fear of fat, and willpower (i.e., beliefs about the controllability of weight and fat). The results showed that respondents’ experiences of weight-based stigmatization, BMI, and gender are the most important predictors of negative attitudes towards obesity. The frequency of experiences of weight-based stigmatization was associated with increased negative attitude scores. Furthermore, men and lower weight individuals appeared to be more critical of obesity, whereas women were more afraid to gain weight. These findings inform prevention and intervention efforts regarding weight-based stigma.