Peter Nilson (17 October 1937 – 8 March 1998) was a Swedish astronomer and novelist. Active at Uppsala University, he compiled a catalogue of galaxies. He was appreciated for a number of essay books (primarily about science) and for a number of science fiction novels like Rymdväktaren, or "The Space Guardian" and Nyaga.
He was born in a Smålandian village and under the early teens a farmer, but science, with its celebrities such as Charles Darwin and Albert Einstein made such an impression on him, as to motivate him to accomplish college studies by letter correspondence. In the early 1960s he began his studies in Uppsala University, initially in mathematics, and thereafter theoretical physics, aesthetics, history of ideas and astronomy.
He was elected a member of the Royal Swedish Academy of Sciences in 1993.