下渗经济学（英语：trickle-down economics，又译为滴流经济学、渗滴式经济学、滴漏经济学）是源于美国的经济术语，用于讽刺给富人减税可惠及穷人的主张（如列根经济学、供给面学派与自由市场）。该主张认为政府对富人阶级减税与提供经济上的优待政策，将可改善经济整体，最终会使社会中的贫困阶层人民也得到生活上的改善。该主张反对以征税手段来减少社会中的贫富差距，也往往反对对贫穷阶层进行社会救助。左派在美国政治与经济问题讨论中用下渗效应代指该主张，含贬义，多用于讽刺。

"Trickle-down economics", also referred to as "trickle-down theory", is a populist political term used to characterize economic policies as favoring the wealthy or privileged. There is no "trickle down" economics as defined by economists; the term is almost exclusively used by critics of policies with other established names. It is usually associated with criticism of laissez-faire capitalism in general and more specifically supply-side economics.