猪笼草，为猪笼草属植物的统称，是猪笼草科的唯一属，也是多种能够捕食昆虫的多年生草本植物，主产地是热带亚洲地区。其为地生植物，是攀援状的亚灌木。猪笼草拥有独特的吸取营养的器官——捕虫笼，捕虫笼呈圆筒形，下半部稍膨大，因为形状像猪笼，故称猪笼草。在中国的产地海南又被称作雷公壶，意指它像酒壶。这类能够通过捕捉和消化昆虫等小动物来获取营养的植物被称为食虫植物。

1981年的克朗奎斯特分类法单独分出一个猪笼草目，1998年根据基因亲缘关系分类的APG 分类法认为应该将本科纳入石竹目。

Nepenthes (/nᵻˈpɛnθiːz/), also known as tropical pitcher plants or monkey cups, is a genus of carnivorous plants in the monotypic family Nepenthaceae. The genus comprises roughly 150 species, and numerous natural and many cultivated hybrids. They are mostly liana-forming plants of the Old World tropics, ranging from South China, Indonesia, Malaysia and the Philippines; westward to Madagascar (two species) and the Seychelles (one); southward to Australia (three) and New Caledonia (one); and northward to India (one) and Sri Lanka (one). The greatest diversity occurs on Borneo, Sumatra, and the Philippines, with many endemic species. Many are plants of hot, humid, lowland areas, but the majority are tropical montane plants, receiving warm days but cool to cold, humid nights year round. A few are considered tropical alpine, with cool days and nights near freezing. The name "monkey cups" refers to the fact that monkeys have been observed drinking rainwater from these plants.