With the aim to reduce the effects of anthropocentric climate change and achieve a more sustainable future, promotion of sustainable individual behaviour is just as essential as driving political and economic change. As social media are experiencing growth in popularity, online communities in which influencers act as opinion leaders are a promising tool to influence behaviour. The objective of this paper was to examine the role of individuals’ pre-existing value structures and the effectiveness of encouraging pro-environmental behaviour amongst the millennial generation on Instagram. The study design is based on the extended version of goal-frame theory, The Integrated Framework for Encouraging Pro-environmental Behaviour. An experiment survey has been developed to measure current pro-environmental behaviour, value structure and goal-frame, test preferred Instagram posts, and measure intentions to act pro-environmentally in the future. Survey respondents were randomly assigned to a control group, which was not shown any Instagram posts. The experiment tested whether the provision of Instagram posts, which are framed in line with one’s goal-frame, creates a more effective message subsequently leading to an increase in future intentions to act pro-environmentally. The results of the analyses indicated that framing of an Instagram post based on pre-existing goal-frames does create a more effective message but does not lead to an increase in future intentions to act pro-environmentally. The differences in intentions to start acting pro-environmentally were not significantly different between the experiment and control group. Further analysis revealed that the strongest predictor to increase intentions to act in line with the environment is a combination of high accessibility to a normative goal-frame (biospheric and altruistic values), low accessibility to a gain goal-frame (egoistic values) and university education. Additionally, it was detected that females are more likely to engage in pro-environmental behaviour, to have higher intentions to adjust their lifestyle as well as accessibility to a normative goal-frame. Implications of this study can be applied to future research as well as help organizations and governments to develop more targeted sustainable consumption campaign and policies.