The Vorkosigan Saga is a series of science fiction novels and short stories set in a common fictional universe by American author Lois McMaster Bujold. The first of these was published in 1986 and the most recent in May 2018. Works in the series have received numerous awards and nominations, including five Hugo Award wins including one for Best Series.

The point of view characters include women (Cordelia in Shards of Honor, Barrayar, and Gentleman Jole and the Red Queen; Ekaterin in Komarr, A Civil Campaign, and The Flowers of Vashnoi), a gay man (Ethan of Athos), a pair of brothers, one of whom is physically disabled and the other a clone (Miles and Mark Vorkosigan), and their cousin (Ivan Vorpatril), together with some minor characters (e.g., Miles's bodyguard Roic, family friend Kareen Koudelka, and the runaway Jin).

The various forms of society and government Bujold presents often reflect contemporary politics. In many novels, there is a contrast between the technology-rich egalitarian Beta Colony (or more generally, galactic society) and the heroic, militaristic, hierarchical society of Barrayar, where personal relationships must ensure societal continuity. Miles Vorkosigan, the protagonist of most of the series, is the son of a Betan former ship captain mother and a Barrayaran aristocrat father.

Humanity has colonized a galaxy in which there are no competing intelligent species. Since then (at least 400 years before Falling Free or 600 years before Shards of Honor), dozens of planets have been colonized and have developed divergent cultures. Barrayar was colonized and then lost contact with the rest of the galaxy, suffering a "Time of Isolation", after which it was reconnected. Due to apparent nuclear warfare that has left large areas too radioactive to inhabit, low genetic diversity on Barrayar during the time of isolation, as well as the effects of mutagenic compounds found in native Barrayaran plants, a cultural phobia about mutation developed that leads to a high level of xenophobia. Within the series, exploration and colonization of new planets is still ongoing, most notably on the planet Sergyar.

Interstellar travel is achieved by "jumping" from solar system to solar system via spatial anomalies known as wormholes that create tunnels in a five-dimensional space. Typically wormholes are bracketed by space stations, military or commercial, which provide ports for jump travel. Stations may be owned by planetary governments, or by specific commercial organizations, or they may be completely independent of any planetary organization. Barrayar's original wormhole collapsed, a rare event leading to the Time of Isolation. Barrayar was later re-discovered via a wormhole jump from Komarr. Komarr allows the neighboring Cetagandan empire to use their wormhole to conquer Barrayar, and is later conquered in its turn when Barrayar eventually defeats the Cetagandans.

The stories feature several planetary systems, each with its own political organization, including government by corporate democracy, rule by criminal corporations, monarchies, empires and direct democracies. In most cases, there is a single government which dominates the entire planet (exceptions include Jackson's Whole and Earth). Both Cetaganda and Barrayar have empires, acquired by conquering other planets via neighboring wormholes.

As a tool to simplify the writing process, Bujold devises a standard system of timekeeping universal to all planets regardless of the length of their day and year. Bujold herself has commented that her posited system is neither technologically nor economically feasible, but is rather a convenience for storytelling.

Most of the technology in the series is based on 20th-century engineering situations, projected into null-g or alternative solar system situations. Biomedical advances such as cloning, artificial wombs (named "uterine replicators") and cryochambers to preserve and revive recently deceased people are featured heavily in the series.