This investigation examined negative and positive impacts and socio-cultural changes of the two Karen communities due to ecotourism. It was found from the investigation that socio-cultural structures of the communities have not changed much, but there have been some adaptations in accordance with surrounding social changes. The communities have maintained their self-reliant production process as well as their neighborly kin relationships. Although they have converted to Christianity, they have still maintained their value system of respect to nature, which is controlled by supernatural entities. Ecotourism has revived their pride in their ethnic identity, job creation, and brought about income generation, and a reduction of forest destruction. The negative impacts of ecotourism have included pollution and disturbances of personal space. The communities have been able to develop ecotourism as an alternative activity for economic development in the form of a community enterprise in conjunction with cultural and wisdom conservation. Moreover, it has brought about revitalization, initiating a collective learning process of natural resource conservation and sustainable development.