酒石酸钾钠（化学式：NaKC₄H₄O₆·4H₂O），也称酒石酸钠钾、罗氏盐、罗谢尔盐，是酒石酸钠与酒石酸钾形成的复盐。它是无色至蓝白色正交晶系晶体，可溶于水，微溶于醇，味咸而凉，水溶液呈微碱性。60°C时开始失去结晶水，215°C时失去其全部结晶水。

两摩尔的酒石酸氢钾溶于水加热，加入一摩尔碳酸钠，趁热过滤，不溶物干燥结晶，即得到酒石酸钾钠。

酒石酸钾钠可用作缓泻剂、食品添加剂（E编号为E337）、压电组件，也可作化学试剂，用于配制菲林试剂、双缩脲试剂以及作为制作镜背银层时的还原剂。

Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a double salt of tartaric acid first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle, France. Potassium sodium tartrate and monopotassium phosphate were the first materials discovered to exhibit piezoelectricity. This property led to its extensive use in "crystal" gramophone (phono) pick-ups, microphones and earpieces during the post-World War II consumer electronics boom of the mid-20th Century. Such transducers had an exceptionally high output with typical pick-up cartridge outputs as much as 2 volts or more. Rochelle salt is deliquescent so any transducers based on the material deteriorated if stored in damp conditions.