Triffids are referenced in the opening number of the stage/film musical The Rocky Horror Show: "I really got hot when I saw Janette Scott fight a triffid that spits poison and kills." Janette Scott played the role of Karen Goodwin in the 1962 film adaptation.
According to director Danny Boyle, it was the opening hospital sequence of The Day of the Triffids that inspired Alex Garland to write the screenplay for 28 Days Later.
The short story "How to Make a Triffid" includes discussions of the possible genetic pathways that could be manipulated to engineer the triffids from Wyndham's story.
The web series Welcome to Sanditon references triffids numerous times, in particular the novel and 1981 BBC adaptation.