<p>Healthcare professionals extensively use social media. Despite initiatives to teach about its use, there remains a gap in effective assessment methods for determining when learners are ready for professional social media engagement. The objective of this study is to develop Entrustable Professional Activities (EPAs) to support competency-based assessment of learners’ social media use. From June to October 2022, the primary author team (IZ, STL, TK, DH, MM) engaged 37 experts in health professions-related social media use from multiple specialties in a multi-round, online, modified Delphi process to develop EPAs for healthcare professionals’ social media use. These physicians are recognized in their fields as social media leaders, having contributed to publications on social media, assumed leadership roles in social media in journals or institutions, developed social media use curricula, and/or were prolific social media users. They evaluated EPA statements drafted by the primary authors on a 5-point Likert-like scale and observability (yes/no). EPAs rated as extremely/very/moderately important and observable by at least 70% of participants were selected for the final EPA statement set. Descriptive statistics facilitated quantitative analysis. Out of 32 participants who accepted the invite, 24 (75%) completed all three rounds of the study. Following the third round, a list of 8 EPAs was finalized, with &gt; 80% consensus on all EPAs. These 8 social media EPAs were categorized into the Professional Development, Education, and Advocacy domains. Expert-informed EPAs for health professionals’ social media use may guide those in training using social media in the domains of Professional Development, Education, and Advocacy.</p>