树木学（英文：Dendrology，dendro源自古希腊语：δένδρον，，其意义为dendron，表示“树木”的意思；logy源自古希腊语：-λογία，意义为-logia，表示“科学”或者“研究”的意思。）亦称木材学或木质学（英文：Xylology，源自古希腊语：ξύλον，意义为ksulon，表示“木材”的意思。）。

树木学为一种专门研究木本植物分类的学科，研究对象以乔木为主，灌木与木质藤本植物次之，研究范围包含树木分类方法、体系、分类群（如科、属、种）、树木型态、构造、生态、分布、用途等等，在植物分类学领域中，许多植物科别底下的成员除了木本植物之外，通常也包含了非木本植物，因此树木学也可视为狭义的植物分类学。

Dendrology (Ancient Greek: δένδρον, dendron, "tree"; and Ancient Greek: -λογία, -logia, science of or study of) or xylology (Ancient Greek: ξύλον, ksulon, "wood") is the science and study of wooded plants (trees, shrubs, and lianas), specifically, their taxonomic classifications. There is no sharp boundary between plant taxonomy and dendrology; however, woody plants not only belong to many different plant families, but these families may be made up of both woody and non-woody members. Some families include only a few woody species. Dendrology, as a discipline of industrial forestry, tends to focus on identification of economically useful woody plants and their taxonomic interrelationships. As an academic course of study, Dendrology will include all woody plants, native and non-native, that occur in a region. A related discipline is the study of Sylvics, which focuses on the autecology of genera and species.