Waste management in urban areas is an increasingly complex challenge, including in Yogyakarta City, following the temporary closure of the Piyungan Regional Final Processing Site. Therefore, serious attention is needed to address the primary sources of waste, one of which is household waste. Food surpluses that are not adequately managed have a high potential to become food waste, which hurts both the environment and the sustainability of food security. This study purpose to determine the factors that Influence food surpluses at the household level and examine the effect of food surpluses on the utilization of leftovers, as well as the role of shopping routines as a moderator of social relations on food surpluses in Yogyakarta City. This study is a quantitative descriptive study. The primary data used were derived from questionnaires completed by 114 respondents. PLS-SEM was used to test the hypotheses. The findings show that shopping routines and social relations have a significant positive Influence on rising household food surpluses, while shopping planning routines do not show a significant impact. Food surpluses have a considerable positive impact on the utilization of leftovers, and shopping routines significantly moderate the effect of social relations on food surpluses. Thus, handling food surpluses within wise consumption patterns and rising food literacy at the household level is an essential strategy for decreasing waste quantity, mitigating adverse environmental influences, and enhancing food security. This research is supposed to deliver empirical roles to the construction of sustainable food and waste management strategies at the household.