Lignum vitae () is a wood, also called guayacan or guaiacum, and in parts of Europe known as Pockholz or pokhout, from trees of the genus Guaiacum. The trees are indigenous to the Caribbean and the northern coast of South America (e.g.: Colombia and Venezuela) and have been an important export crop to Europe since the beginning of the 16th century. The wood was once very important for applications requiring a material with its extraordinary combination of strength, toughness, and density. It is also the national tree of the Bahamas, and the Jamaican national flower.

The wood is obtained chiefly from Guaiacum officinale and Guaiacum sanctum, both small, slow-growing trees. All species of the genus Guaiacum are now listed in Appendix II of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) as potentially endangered species. G. sanctum is listed as Near Threatened by the IUCN Red List. Demand for the wood has been reduced by modern materials science, which has led to polymers, alloys and composite materials that can take lignum vitae's place.