California Golf Club of San Francisco — Ransomware Incident Claimed by Qilin
- Victim: California Golf Club of San Francisco
- Claimed by Qilin
- Date claimed: 2025-10-07
- Country: US
- Sector: Hospitality and Tourism
California Golf Club of San Francisco, commonly known as Cal Club, is a private golf club established in 1918, originally located in Ingleside before moving to its current 425-acre site in 1924.