Pentacyclic triterpenes have been found in many plants and may be isolated from any part of the plant. Triterpene derivatives were shown to have biological activities including anti-HIV-1 and anti-cancer activities. The modes of action of the anti-HIV-1 triterpenes have been reported to be associated with the virus entry, reverse transcription, virus assembly and maturation. This review will focus on the mechanisms of action of anti-HIV triterpenes and the structural features that contribute to their anti-HIV-1 activity and site of action.