柠檬水是一种以柠檬调味的水饮料，起源于17世纪的法国巴黎。部份柠檬水饮料加入了二氧化碳制成汽水，最著名的品牌是雪碧和七喜。

在香港，柠檬水时常简称为柠水，与港式柠檬茶一样，一般必定配有2块至4块切片柠檬在杯中，客人可用配备的匙或饮管将柠檬摏搞以调节酸性。另外，热饮中加糖的饮法与西方不一定加糖的饮法相异。

不少上班族常受胃痛困扰，很多时与饮食习惯有关，近年很多人深信饮柠檬水、果醋可排毒护肤，或食西柚有助减肥，肠胃科医生陈安安表示虽然柠檬、西柚及果醋都属有益食物，但不宜长期空腹进食或饮用，否则会刺激更多胃酸分泌，建议偶尔进食，并宜先吃其他食物「打底」，让食物消化的过程可稀释胃酸，减少对胃部刺激。

Lemonade is the name for a number of sweetened beverages found around the world, all characterized by lemon flavoring.

Most lemonade varieties can be separated into two distinct types: cloudy, and clear, each known simply as "lemonade" in countries where dominant. Cloudy lemonade, generally found in North America and India, is a traditionally homemade drink made with lemon juice, water, and sweetened with cane sugar or honey. Found in the United Kingdom, Ireland, Australia, and New Zealand, clear lemonade is a lemon, or lemon-lime flavored, carbonated soft drink.