- 简体中文名: 雪乐山公司
- 别名: Sierra On-Line
- 父公司: CUC International (1996–1997), Cendant (1997–1998), Vivendi (1998–2008), Activision (2008–present)
- 官方网站: sierra.com
Sierra Entertainment (previously Sierra On-Line, commonly referred to as Sierra) is an American publisher founded in 1979 as On-Line Systems by Ken and Roberta Williams. Based in Oakhurst, California and later in Fresno, California, the company is owned by Activision, a subsidiary of Activision Blizzard.