is a Dutch photographer and self-publisher of documentary work, particularly of areas of the former Soviet Union and works as co-head of the photography department of the Royal Academy of Arts in The Hague.

Hornstra studied Social and Legal Services at Utrecht University of Applied Sciences from 1994 to 1998; for a year from summer 1996, he interned and then worked as a probation officer. From September 1998, he worked for over eight years as a host and bartender at Muziekcentrum Vredenburg in Utrecht. From 1999 to 2004, he studied photographic design at Utrecht School of the Arts.

Since graduation Hornstra has combined editorial work for newspapers and magazines with more personal, longer-term documentary work in the Netherlands, Iceland, and the former Soviet Union. Hornstra considers himself a maker of photographic documentaries rather than a photographer; when not photographing for a particular purpose, he does not carry a camera. Further, he sees books as more important than exhibitions, and regards his own editing, publication and marketing of books of his photography as an important part of his work.