糖耐力测试（Oral glucose tolerance test, OGTT）是一种测试血糖在人体内代谢水平的医学实验。

具体步骤是，要求被测试对象在空腹情况下喝下75克无水葡萄糖或82.5克含一分子水的葡萄糖，然后在两小时测试血糖变化情况。儿童按1.75克/公斤计算，但不超过75克。

根据世界卫生组织颁布的标准，如果在糖耐力测试中，2小时后血糖高于11.1 mmol/l，则可以确诊为糖尿病。

由于该测试是属于口服血糖来增加血糖水平值，当病人已被确诊为糖尿病时不宜做此项试验，所以仅对血糖高于正常值而又未达到诊断糖尿病标准时才进行试验。但是这个试验所导致的血糖增高仅仅是暂时的，患者不用担心会由于这项试验导致病情恶化。如果患者实在不适宜做此项检查，还有其他的糖尿病检测方法，如糖化血红蛋白（GHbA1）和糖化血浆白蛋白进行测定。

The glucose tolerance test is a medical test in which glucose is given and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, insulin resistance, impaired beta cell function, and sometimes reactive hypoglycemia and acromegaly, or rarer disorders of carbohydrate metabolism. In the most commonly performed version of the test, an oral glucose tolerance test (OGTT), a standard dose of glucose is ingested by mouth and blood levels are checked two hours later. Many variations of the GTT have been devised over the years for various purposes, with different standard doses of glucose, different routes of administration, different intervals and durations of sampling, and various substances measured in addition to blood glucose.