The purpose of this research is to better understand what factors influence on households’ waste sorting behavior at source in Mongolia. To accomplish the goal, this study conducted online survey with self-report questionnaire method and the 353 participants’ data were collected through Facebook groups and pages related to house owners’ associations and waste recycling related non-profit organizations. The results show that the underlying factors determining the intention of waste sorting at source are (1) motivational bases such as prior beliefs and social norms; (2) and an ability/knowledge about the waste sorting at source. Furthermore, the intention is crucial predictor of the real behavior of waste sorting at source, but the most important one is an opportunity to do so. The conclusions and the recommendations are provided.