The purpose of this research is to provide a complete understanding of the river water quality state in key Southeast Asian cities and determine the factors influencing water quality. A thorough search of electronic databases such as Scopus, Web of Science, and Google Scholar was conducted. A checklist derived from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria was used to assess the quality of the selected studies. The study included 18 studies that examined several parameters such as pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and fecal coliform (FC). The findings suggest that water quality in Southeast Asian cities' major rivers is generally bad, with notable exceptions.