<p>Sorting plastic waste at home can help reduce the environmental impacts. Nevertheless, the city of Balikpapan shows a low level of engagement, with less than 40% of the households involved in this activity. Further investigation is required to understand the underlying mechanisms. This study investigates the impact of the informal waste sector, municipal solid waste facilities, environmental knowledge and people’s perceptions of household plastic waste segregation in Balikpapan City. Structural equation modeling (SEM) was used to analyze the data. The findings show that all factors positively affect individuals’ opinions of plastic waste segregation. Approximately 66.4% of individuals’ understanding of the environment was influenced by the inclusion of municipal solid waste facilities, whereas municipal solid waste facilities influenced the existence of the informal waste sector by 35.2%. The combination of factors in the model had an effect of 72% on the observed perception of plastic waste segregation. These findings suggest that a balanced approach, prioritizing solid waste facilities, education, and informal waste sector integration, is crucial for developing an efficient and sustainable waste management system especially in Balikpapan City.</p>