James May's 20th Century is a television series first aired on 10 July 2007 on the British terrestrial channel BBC Two. The series is a co-production by the BBC and the Open University.

The series covers various inventions and discoveries over the past century with some reference to discoveries made before the past century. The show features the eponymous James May, exhibiting and discussing the implications of many of the major advances and inventions made during this period. Each episode features some theme, which was discussed in depth during the show, often following sequential advances in chronological order. The programme is now shown on Eden, Yesterday and Dave. The theme tune is called "The Long Boot", by Jeff Knowler.