The Atlas I was a US expendable launch system manufactured by General Dynamics in the 1990s to launch a variety of satellites. Though the Atlas I was marketed as a new rocket, it was mostly a re-brand of the Atlas G/H for commercial payloads. The Atlas G and H launched mostly governmental satellites.

Atlas I was the last use of the classic Atlas design with three engines, a jettisonable booster section, and two vernier engines. Atlas II, while retaining most of those features, replaced the verniers with a hydrazine roll control system.