In recent years, anti-rape culture and anti-rape communication have taken new forms, including the diverse use of tweets and hashtags, prompting so-called hashtag feminism. In this article, we examine digital and analogue discussions propelled by a notorious case of gang-rape in Spain in 2016, which became known as “La Manada”/The Wolf Pack” (hereafter TWP). Hundreds of thousands of Spanish women took to the streets in protest during the three years of the case and their chants also flooded social media. This article is the result of a hashtag ethnography of the hashtag #SisterIdobelieveyou. We argue that the synchronized performative action of “believing” undertaken by thousands of Twitter users, along with mass demonstrations on the streets, had a triple effect: it gave rise to a “virtual” community of sisterhood, challenged prevalent rape culture and gender stereotypes in Spanish society, and provided social media users with a new framework to conceive of and express themselves about sexual violence.