Grounded in the Social Identity Model of Collective Actions (SIMCA), this study examines the role of strategic internal communication—specifically, transparent communication—in fostering gender equality at work via women’s workplace activism: collective actions and communicative behaviors. Results from an online survey of 402 female employees in South Korea suggest that transparent communication plays an important role in increasing women’s identification with their organizations, thereby fostering their efficacy and reducing perceived injustice. This, in turn, increased their active communicative behaviors and collective actions for promoting gender equality in the workplace. Theoretical implications for strategic internal Diversity, Equity, and Inclusion (DEI) communication are discussed along with avenues for future research.