Cosmos: A Personal Voyage is an educational television series written and narrated by astronomer and writer Carl Sagan in 1980, and was also published in book form. It is best known for its presentation of a wide variety of scientific topics — astronomy, physics, biology, evolution, environmentalism, nuclear power, and more — in Layman's Terms, making both the wonder and the terminology accessible to the public. It also had cutting edge special effects for the time it was produced.

The series has been credited with inspiring an entire generation of scientists and formed a template for nearly every mainstream science program that followed. It was re-released as a DVD collection with commentary by Sagan, mainly to discuss where Science Marches On. Even today, it remains remarkably relevant; although some of the facts are dated, the majority of the principles and theories discussed by the show remain intact.

In 2014 a new series produced by the same development team as the original aired called "Cosmos: A Sapcetime Odyssey". The series aired on Fox and was hosted by Neil deGrasse Tyson. That was followed by a third series "Cosmos: Possible Worlds" on National Geographic Channel in 2020.