The purpose of the present study is to expand upon the tenets of Self-Determination Theory within a context of social media (SM). Specifically, we are assessing the impact of dimensions of autonomous motivation on Millennials’ support for charitable causes, in the social media domain. It has been said that ‘Millennials’ (those born after 1980) will be the most influential generation since the Baby Boomers. They are socially aware and civic-minded and engaged in helping societal causes. Furthermore, the relationship the Millennial shares with arguably the most influential form of modern technology, social media, is truly groundbreaking. Social media has proven itself to be a powerful tool, not only for businesses, but also for society as a whole. The total sample consisted of 592 participants from two separate studies: Study 1 (CURE Foundation Denim Night Party in support of breast cancer awareness) and Study 2 (Dans la rue/Five Days for the Homeless charity to raise awareness for youth homelessness). Results indicated that integrated extrinsic motivation significantly predicted online-, cause-, and event-related behaviour intentions, while intrinsic motivation to know and experience stimulation significantly predicted all three behaviour intentions. Both the managerial and theoretical implications of this study are addressed herein, as well as future research avenues.