An assessment tool in the area of sustainability literacy stands in a need of a strategic methodology for an exhaustive and logical framework encompassing both theoretical and experiential sub-structure[1]. This study describes the development of a Sustainability Literacy Scale to assess the sustainability literacy of the Secondary School Students in India. The scale is grounded on strong theoretical and conceptual foundations of sustainability literacy rooted in Triple Bottom Line Theory [2]and KAP Model [3]. The instrument focuses upon an integrated span of components encompassing Knowledge, Mindset and Performance [4,2] which is compendious of the economic, social, environmental and cultural aspects [5, 6]. A total of 64 statements are framed giving due importance to all the three components – knowledge, mindset and performance, each integrated with the sustainability domains – Environmental, Social, Economic and cultural. The component knowledge is assessed through a test and the components mindset and performance are assessed through a five-point scale- making the developed tool for assessing sustainability literacy a ‘Multi-dimensional Sustainability Literacy Instrument’. After enduring expert validation ensuring face and content validity, the scale has been subjected to a pilot study among 563 secondary school students. Data collection is being done from different zones of the state as southern, northern and central parts which helps in including data from various geographical areas (hilly, costal and plain). This is to ensure an incorporated data from different cultural, social, environmental and economic background which are the key factors of the Sustainability Literacy Scale. Factor Analysis is done to explore and confirm the dimensionality of the scale (with the KMO value of 0.894), while Item Analysis has been executed for construct validation ensuring item effectiveness and refinement. For the test items, validation is been done through ensuring the accepted values of Discriminative Power and Difficulty Index. The final instrument after the validation consists of 56 statements retained. The internal consistency of the developed scale is established with Cronbach’s Alpha with a value of 0.814 and the test KR-20 value of 0.761. The outcome confirms The Sustainability Literacy Scale as a significant contribution in the field of sustainability, which can effectively assess the sustainability literacy of individuals considering the global perspective as environmental, social, economic and cultural aspects.