Abstract: Consumer-driven sharing and creation activities are valuable engagement activities as they help spread awareness and interaction for brands on social media. Loyal fans of brand pages are an important audience for brand-related social media engagement, as they are more likely to recommend and advocate for brands. However, little is known about what motivates loyal fans to engage in these valuable activities. This study takes a novel approach by examining self-expansion as a driver that prompts loyal fans to action. When brands offer self-expansive opportunities on their pages, in the form of new knowledge, new perspectives (e.g. awareness on social issues), and exciting experiences, fans may incorporate these in their sense of self (self-page inclusion) and reciprocate by investing their own resources to brand pages. A survey was conducted with 238 millennial users who have a favorite brand page on Instagram. The findings show that the more fans gain opportunities for self-expansion from their favorite pages, the more likely they are to share and create brand-related content. Brand page flow and self-page inclusion are also important drivers. Further, specific page experiences are identified that may enhance the effects of these drivers. Managerial implications are included on how to apply these findings to social media content strategy.