Trosius Aper was a grammarian of ancient Rome who served as one of two Latin tutors for the Roman emperor Marcus Aurelius, along with Tuticius Proculus. He was from Pola (modern Pula) in Istria, and was assigned to Aurelius as a tutor around 132 or 133 AD. As a tutor, Aper would have Aurelius read classical works out loud, and memorize them, later commenting on stylistic matters, and drawing philosophical lessons from the text for his pupil.
- van Ackeren, Marcel (2012). A Companion to Marcus Aurelius. Blackwell Companions to the Ancient World. 96. Wiley-Blackwell. p. 141. ISBN 9781405192859. Retrieved 2016-02-21.
- Stephens, William O. (2011). Marcus Aurelius: A Guide for the Perplexed. Guides for the Perplexed. A&C Black. p. 7. ISBN 9781441101792. Retrieved 2016-02-21.
- Birley, Anthony R. (2012). Marcus Aurelius: A Biography. Roman Imperial Biographies. Routledge. p. 40. ISBN 9781134695690. Retrieved 2016-02-21.
- Adams, Geoffrey William (2013). Marcus Aurelius in the Historia Augusta and Beyond. Reference, Information and Interdisciplinary Subjects Series. Rowman & Littlefield. p. 61. ISBN 9780739176382. Retrieved 2016-02-21.