Two characteristics of millennial behaviour motivate the present study–an increasing concern for various life issues, and an increasing level of social media usage. In the present study, we focused on millennials’ societal concerns, financial concerns and social exclusion concerns and examined how these concerns influence social media behaviour. Adopting the compensatory consumer behaviour framework, we proposed that millennials’ social media behaviour can be understood as a form of compensatory consumption, that is, a coping mechanism for dealing with major life concerns. Data collected from a commercial survey of Australian millennials supported most of our hypotheses. We observed that social exclusion concerns directly influenced social media behaviour, whereas societal and financial concerns influence social media behaviour indirectly through influencing social exclusion concerns. Our proposed model explained more than half of the variance in social exclusion concerns, and more than one-third of the variance in social media behaviour.