棕榈科（学名：Arecaceae）又称槟榔科，棕榈目下的一个科。目前已知棕榈科下有202属，大约2,800余种。

本科植物一般是单干直立，不分枝，一般为乔木，也有少数是灌木或藤本植物。叶子极大互生，簇生于树干顶部，但在藤本中散生，全缘、掌状或羽状分裂的大叶。花小，通常为淡绿色，两性或单性，排成圆锥花序或穗状花序，多少为一至多枚大而呈鞘状的苞片所包围，花被6裂2列，裂片离生或合生，雄蕊通常6枚，子房上位，一般有1－3室，每室有胚珠一枚。是单子叶植物中唯一具有乔木习性，有宽阔的叶片和发达的维管束的植物类群。

The Arecaceae are a botanical family of perennial lianas, shrubs, and trees commonly known as palm trees. (Owing to historical usage, the family is alternatively called Palmae.) They are flowering plants, the only family in the monocot order Arecales. Roughly 200 genera with around 2600 species are currently known, most of them restricted to tropical, subtropical, and warm temperate climates. Most palms are distinguished by their large, compound, evergreen leaves arranged at the top of an unbranched stem. However, palms exhibit an enormous diversity in physical characteristics and inhabit nearly every type of habitat within their range, from rainforests to deserts.