氢氯噻嗪（英语：Hydrochlorothiazide，简称HCTZ、HCT或HZT）是一种利尿剂。通常用来治疗高血压及因液体堆积造成的水肿。其他用途还包含治疗尿崩症和肾小管性酸中毒，它也可以减轻高钙尿症，从而降低肾结石的风险。此外，此药物也经常作为治疗高血压的第一线药物。氢氯噻属于口服药物，有时会混合其他降血压药物制成复方药锭，以加强药效 。

氢氯噻嗪被归类在噻嗪类药物，主要是透过减少肾脏的保水作用发挥效果。它将直接地降低血容量，减少回流至心脏的血液及减少心脏泵血量。而长期使用氢氯噻嗪则会使得周围血管阻力降低。

Hydrochlorothiazide (abbreviated HCTZ, HCT, or HZT), is a diuretic medication often used to treat high blood pressure and swelling due to fluid build up. Other uses include diabetes insipidus, renal tubular acidosis, and to decrease the risk of kidney stones in those with high calcium level in the urine. For high blood pressure it is often recommended as a first line treatment. HCTZ is taken by mouth and may be combined with other blood pressure medications as a single pill to increase the effectiveness.