Patrick Demarchelier is a French-born fashion photographer.

Born in Le Havre in 1943, Demarchelier has lived in New York City since 1975. He has worked for magazines such as Glamour, Mademoiselle, Vogue, GQ, and Rolling Stone.

Since 1992 he has worked with Harper's Bazaar, becoming its premier photographer. Demarchelier was awarded the contract for the 2005 Pirelli Calendar. Demarchelier is referenced in the 2006 film The Devil Wears Prada, as the dragon lady, Miranda Priestly (Meryl Streep), often tells Andy (Anne Hathaway), "Get me Demarchelier!" leaving her utterly confused, and the first assistant Emily replying, "I have Patrick!"