月见草属（学名：Oenothera）又称待宵草、晚樱草，属于柳叶菜科的植物。因为本属植物大多数只在夜晚开花、白天凋谢，所以又名「Evening Primrose」。

多年生草本。茎直立，被毛；基生叶丛生，有柄；茎生叶互生，有短柄或无柄，条状披针形，两边有白色短柔毛，边缘有疏锯齿；夏季开黄色花，单生于叶腋，夜开晨闭；圆柱形蒴果，略具四棱。

Oenothera is a genus of about 145 species of herbaceous flowering plants native to the Americas. It is the type genus of the family Onagraceae. Common names include evening primrose, suncups, and sundrops. They are not closely related to the true primroses (genus Primula).