28 Weeks Later is a 2007 post-apocalyptic action horror film directed by Juan Carlos Fresnadillo, who co-wrote it with Rowan Joffé, Enrique López Lavigne, and Jesús Olmo. It is the sequel to 28 Days Later (2002) and the second instalment in its series. The film stars Robert Carlyle, Rose Byrne, Jeremy Renner, Harold Perrineau, Catherine McCormack, Mackintosh Muggleton, Imogen Poots, and Idris Elba. Set six months after the earlier Rage Virus outbreak, it follows the US-led NATO forces' attempt to establish a safe zone in London, the consequences of two young siblings breaking protocol, and the resulting reintroduction of the virus into Britain.
On a budget of $15 million, principal photography began in August 2006 and ran for ten weeks. Danny Boyle and Alex Garland returned as executive producers, and Boyle also contributed second-unit footage that includes parts of the opening sequence. Promotion included the release of a graphic novel tie-in and a projected biohazard warning staged on the White Cliffs of Dover ahead of the film's general release.
The film was released theatrically on 11 May 2007 and is a co-production involving the United Kingdom, United States, and Spain, with distribution handled by 20th Century Fox in the UK and Fox Atomic in the US. It earned $72.3 million worldwide and generally positive reviews from critics, who largely praised it as a tense, well-crafted militarised disaster horror with a standout opening and set pieces, while noting uneven originality, clarity, and plausibility compared with its predecessor. Commentators also noted themes disparaging American militarised crisis management, particularly the Bush administration's 2003 invasion of Iraq. Major plot elements in the film have been recontextualised in the third instalment, 28 Years Later, which was released on 20 June 2025.