Klaus is a German given name and surname. It originated as a short form of Nikolaus, a German form of the given name Nicholas.

Klaus may also refer to:

Karl Friedrich May ( /ˈmaɪ/ MY; 25 February 1842 – 30 March 1912) was a popular German writer, noted mainly for adventure novels set in the American Old West, (best known for the characters of Winnetou and Old Shatterhand) and similar books set in the Orient and Middle East (with Kara Ben Nemsi and Hadschi Halef Omar). In addition, he wrote stories set in his native Germany, in China and in South America. May also has written poetry and a play, and composed music; he also was proficient player of several musical instruments. Many of his works were filmed, adapted for the stage, turned into audio dramas or into comics. A highly imaginative and fanciful writer, May never visited the exotic places featured in his stories until late in life, when the clash between fiction and reality led to a complete change in his work.

Asteroid 348 May is named in his honor.^{[citation needed]}

Karl May was born into a family of poor weavers in Ernstthal, Schönburgische Rezessherrschaften (later part of the Kingdom of Saxony). He was the fifth child out of fourteen, nine of whom died within a few months of their birth. According to his autobiography, he suffered from visual impairment shortly after birth and regained his eyesight after treatment at the age of five. Possibly a lack of vitamin A led to night blindness, which then grew worse.