肾小管性酸中毒(Renal tubular acidosis、RTA)涉及在体内酸的积累酸中毒(acidosis/酸血症)、起于肾脏未能适当地酸化尿液而造成的医学疾病。当血液通过肾脏的过滤，滤液穿过肾单位小管，作为尿液排入膀胱之前允许交换盐、酸当量，及其他的溶质。由RTA导致的代谢性酸中毒(metabolic acidosis)可能会引起无论是从肾单位(近曲小管(Proximal convoluted tubule))的滤液早期部分回复足够的(碱性)碳酸氢根离子、或则从肾单位(远曲小管(Distal convoluted tubule))的滤液后期部分回复不足够的(酸)氢离子分泌的两种情况之衰竭。虽然代谢性酸中毒也发生在那些肾功能衰竭定患者中，而术语RTA是指个人有较差的泌尿酸化、对比于另外运转良好的肾脏。有几种不同类型的RTA的存在，这些不同的RTA都由不同的综合征、或不同的病因所引起。

Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine. When blood is filtered by the kidney, the filtrate passes through the tubules of the nephron, allowing for exchange of salts, acid equivalents, and other solutes before it drains into the bladder as urine. The metabolic acidosis that results from RTA may be caused either by failure to recover sufficient (alkaline) bicarbonate ions from the filtrate in the early portion of the nephron (proximal tubule) or by insufficient secretion of (acid) hydrogen ions into the latter portions of the nephron (distal tubule). Although a metabolic acidosis also occurs in those with renal insufficiency, the term RTA is reserved for individuals with poor urinary acidification in otherwise well-functioning kidneys. Several different types of RTA exist, which all have different syndromes and different causes.