Ang Lihim ng Isang Pulo
 Ang Lihim ng Isang Pulo: Nobelang Tagalog (kasaysayang ukol sa mga unang panahon) – The Secret of an Island: A Tagalog Novel (history about times past) – is a Tagalog-language novel written in 1926 by Filipino novelist Faustino S. Aguilar. The 353-page novel was first published by Sampaguita Press in the Philippines in 1927. It was republished in Manila by Benipayo Press in 1958.