非那西丁（Phenacetin，或译非那西汀），化学式C₁₀H₁₃NO₂，在室温是白色结晶固体，熔点约134℃，是一种在许多国家被禁售的药物。

非那西丁在1887年发明， 主要作为止痛药使用。通常每日300至500毫克的剂量便达到止痛效果。它亦有退烧作用。

Phenacetin (or acetophenetidin) is a pain-relieving and fever-reducing drug, which was widely used between its introduction in 1887 and the 1983 ban imposed by the FDA on its use in the United States. Its use has declined because of its adverse effects, which include increased risk of certain cancers and kidney damage. It is metabolized as paracetamol (acetaminophen), which replaced it in some over-the-counter medications following the ban on phenacetin.