Renārs Kaupers (sometimes anglicised as Reynard Cowper; born 1 September 1974, in Jelgava) is a Latvian pop/rock singer, instrumentalist, and songwriter who is the vocalist of the band Prāta Vētra (known internationally as Brainstorm).

Kaupers graduated from University of Latvia in 1996 with a degree in journalism. He can speak at least three languages with fluency: English, Latvian, and Russian. Kaupers' ancestors were probably Baron Friedrich von Stuart from Courland (1761–1842) and Immanuel Kant's niece Henrietta Kant.

He is the lead singer of the Latvian pop/rock band Brainstorm, which came third at the Eurovision Song Contest 2000 with their song "My Star". In 2001, Renārs received the Latvian Film Prize as the best actor for his role as Juziks in the film Vecās pagastmājas mistērija (The Mystery of the Old Parish House).

He hosted the Eurovision Song Contest 2003 in Riga, Latvia, with co-host Marija Naumova (stage name Marie N), and also hosted Congratulations, the Eurovision 50th anniversary concert in Copenhagen, Denmark, with Katrina Leskanich.

Kaupers' sons Edgars and Emīls run the indie-pop group Carnival Youth.