To date, there is no such scale that may precisely measure mores of the customer base for the ecotourism industry. Therefore, a thematic analysis of literature has been conducted by examining various good quality research works on intrinsic characteristics eliciting pro-environmental actions. Based upon the thematic analysis, a new scale of measure has been proposed with the help of 17 scholars and 15 practitioners hailing from different countries by mutually agreed intended meanings and breadth of the theoretical concepts. The new scale has 4 dimensions comprising a pool of 32 items, which has been empirically validated through the data collected from 268 Malaysian tourists. The dimensions are: sense of obligation to care for the natural environment, sense of obligation to practice eco-friendly activities, sense of obligation to purchase eco-friendly products, and sense of obligation to support eco-friendly inventions. The theoretical and managerial implications together with research limitations have been discussed.