Secret Agent of Terra is a 1962 science fiction novel by British writer John Brunner. It is the first book of the Zarathustra Refugee Planets series; the other books are Castaways' World (1963) and The Repairmen of Cyclops (1965). Secret Agent of Terra was first published as Ace Double F-133, with The Rim of Space by A. Bertram Chandler.

Brunner later reworked the story for his 1969 novel The Avengers of Carrig.

• Secret Agent of Terra. New York: Ace Books. 1962.
• The Avengers of Carrig. New York: Daw Books. 1980 [1969]. ISBN 0-87997-509-1.

• Tuck, Donald H. (1974). The Encyclopedia of Science Fiction and Fantasy. Chicago: Advent. p. 71. ISBN 0-911682-20-1.
• De Bolt, Joe (1975). The Happening worlds of John Brunner: critical explorations in science fiction. Kennikat Press. pp. 216. ISBN 978-0-8046-9124-6.

• Secret Agent of Terra title listing at the Internet Speculative Fiction Database