ABSTRACT While the intended objective of integrated river basin management (IRBM) is to attain sustainable development, institutional challenges behind environmentally less sensitive society to manage natural resources in a river basin are remained unexplored. Therefore, this study attempted to determine institutional challenges and understand the complexity and interconnectedness of factors affecting policy processes and outcomes of IRBM in the Langat River Basin (LRB), Malaysia using institutional analysis and development (IAD) framework, literature review, field observation and stakeholder interview. This analysis has defined three categories of action arenas of governance structure for IRBM in LRB. Action arena for newly formed river ba...