The present study identified, evaluated, and compared two health belief/attitudinal models (protection motivation theory and the theory of planned behaviour) that explain the decision-making processes associated with both the intention for and engagement in self-care overweight/obesity-reducing behaviours. Multi-model analysis with a sample of 1,100 participants indicated that the theory of planned behaviour offered a better representation of, and provided a more potent theoretical framework than the protection motivation model in explaining the decision-making processes underlying both the intention for and engagement in self-care overweight/obesity-reducing behaviours. Employment of multi-group analysis yielded no significant gender differences in the adoption of overweight/obesity-reducing behaviours, which suggest similar decision-making processes for males and females. The implications of these findings with regard to the role that health beliefs and attitudes play as key predictors of the decision of whether or not to engage in self-care overweight/obesity-related behaviours are discussed.