The Day of the Triffids is a 1951 post-apocalyptic novel about a plague of blindness that befalls the entire world, allowing the rise of an aggressive species of plant. It was written by the English science fiction author John Wyndham Parkes Lucas Beynon Harris, under the pen name John Wyndham. Although Wyndham had already published other novels using other pen-name combinations drawn from his real name, this was the first novel that was published as John Wyndham. It established him as an important writer, and remains his best known novel.
The story has been made into the 1962 feature film of the same name, three radio drama series in 1957, 1968 and 2008, and two TV series in 1981 and 2009. It was nominated for the International Fantasy Award in 1952 and in 2003 the novel was listed on the BBC's survey The Big Read.