Five new species of Syzygium are described from the island of New Guinea. One species, Syzygium neurophyllum, occurs in Papua Province, Indonesia. Four species, S. purpuricarpum, S. rambutyense, S. ridsdalei, and S. watutense occur in Papua New Guinea. Four of the five species are known only from the type gathering, but each is easily diagnosed from congeneric members of Syzygium occurring on New Guinea. The conservation status following IUCN guidelines is proposed for each new species, four of which are considered Vulnerable, and one of which is considered Endangered.