Our excessive consumption of single-use plastic has made this era become a plastic age, thus pro-environmental behaviour (PEB) should become our means of survival. This study aims to test whether norm activation theory which is commonly used to explain PEB on adults, could also shed some light in the same behaviour on children sample. Questionnaires, observation, and focus group discussion were used to obtain data from 533 fifth grade students in Jabodetabek, Indonesia. School environment, cultural background, age, length of study, and where the participants live are controlled. Data were then processed through Structural Equation Modelling (SEM). As predicted, norm activation theory has an adequate goodness of fit. Moreover, this study discovers a new interpretation of the theory, that adverse consequence can directly predict personal norm and PEB, due to the malleability of this theory which is further explained in the discussion. © The Authors, published by EDP Sciences, 2018.