#YesAllWomen first spread after which 2014 California killings?

#YesAllWomen first spread after the 2014 Isla Vista killings in California.

The killings took place on 23 May 2014 near the University of California, Santa Barbara. Elliot Rodger killed six people and injured fourteen others before dying by suicide. His online videos and manifesto contained misogynistic statements, which led to intense public discussion about violence against women, sexual entitlement, harassment, and the wider culture surrounding gender-based abuse.

The hashtag emerged on Twitter in the days afterward, partly in response to #NotAllMen. While #NotAllMen emphasized that not every man commits violence, #YesAllWomen gave women a way to share experiences showing why fear, harassment, and discrimination can shape everyday life even when individual men are not violent.

The campaign quickly expanded beyond the specific California attack. Within days, more than one million posts used the hashtag, turning a conversation about a mass killing into a broader testimony-driven discussion of sexism. “Isla Vista killings” can refer to more than one event, so the relevant answer here is specifically the 2014 attack, not the separate 2001 Isla Vista killings.