Sierra Entertainment
Company
Primary language: English
a.k.a. On-Line Systems, SierraVenture, Sierra On-Line
Official website - Wikipedia (en) - Wikipedia (ja) - Wikidata - Xitter - MobyGames - GameFAQs - VNStat
Sierra Entertainment, Inc. (formerly On-Line Systems and Sierra On-Line, Inc.) was an American video game developer and publisher. Founded in 1979 as On-Line Systems, by Ken and Roberta Williams.