ISET and its sister organization, ISET-Nepal, collaborate closely on the development of joint programs and strategies for regional and global activities. 

ISET-Nepal is a registered NGO in Nepal. Although legally an independent organization, ISET-Nepal is also, by nature, an extension of ISET. By linking together the two organizations, they bring together synergies that exist between resources and capabilities available to both, and the interests of leading individuals within each of them. Wherever possible, ISET and ISET-Nepal collaborate closely on the development and implementation of joint programs and projects. This is a primary goal of both organizations, particularly in relation to activities in South Asia or at the global level where senior staff share joint interests. However, whilst the emphasis in collaboration on projects exists, both ISET and ISET-Nepal, as individual and separate organizations, also develop strategic areas of practice of their own initiative without necessarily involving the other.  

Certain members of the Board of Directors of ISET are also represented on the Board of Directors of ISET-Nepal. In addition, many of the members of ISET-Nepal are leading individuals in Nepal Water Conservation Foundation with whom ISET has a long history of collaboration on regional projects.