The current study examines the positive impact of sustainable product packaging, availability, and retailers on the willingness to buy sustainable products, ultimately leading to sustainable consumption behavior. It also examines how the ascription of responsibility, perceived consumer effectiveness, and perceived policy effectiveness moderate the impact of retailers’ sustainable determinants and sustainable consumption on the willingness to buy sustainable products, drawing on the theory of planned behavior (TPB). Young people from Pakistan were surveyed using a self-administered questionnaire. This study collected 296 valid responses using judgmental sampling and Partial Least Squares Structural Equation Modeling (PLS-SEM) to analyze the data. This study revealed that sustainable product packaging, availability, and retailers have a significant positive relationship with willingness to buy sustainable products, which leads to sustainable consumption behavior. Further, it accordingly validated the moderating effects of ascription of responsibility, perceived consumer effectiveness, and perceived policy effectiveness on the hypothesized relationships.