Contagion is a 2011 American medical thriller film directed by Steven Soderbergh. Its ensemble cast includes Matt Damon, Laurence Fishburne, Jude Law, Marion Cotillard, Kate Winslet, and Gwyneth Paltrow. The plot concerns the spread of a highly contagious virus transmitted through respiratory droplets and fomites, attempts by medical researchers and public health officials to identify and contain the disease, the loss of social order as the virus turns into a worldwide pandemic, and the introduction of a vaccine to halt its spread. To follow several interacting plot lines, the film makes use of the multi-narrative "hyperlink cinema" style, popularized in several of Soderbergh's films. The film was inspired by real-life outbreaks such as the 2002–2004 SARS outbreak and the 2009 flu pandemic.

Following their collaboration on The Informant! (2009), Soderbergh and screenwriter Scott Z. Burns discussed a film depicting the rapid spread of a virus. Burns consulted with representatives of the World Health Organization as well as medical experts such as W. Ian Lipkin and Larry Brilliant. Principal photography started in Hong Kong in September 2010, and continued in Chicago, Atlanta, London, Dublin, Geneva, and San Francisco Bay Area until February 2011.

Contagion premiered at the 68th Venice International Film Festival on September 3, 2011, and was theatrically released on September 9, 2011. Commercially, the film made $136.5 million against its $60 million production budget. Critics praised it for its narrative and the performances, as did scientists for its accuracy. The film received renewed popularity in 2020 due to the emergence of the COVID-19 pandemic.