标准九分（英语：Stanine，是 Standard NINE）的简称，是用 1 至 9 分来描述测验的分数，最高9分，最低1分。标准九分的好处是可以将测验的分数用一位数表示，像性向测验、成就测验的分数常用标准九分来表示。

标准九分是常态化标准分数的一种，主要是利用常态分布的概念，将常态分布的曲线分为九个部份。标准九分的平均值为 5，标准差为 2，单位为半个标准差，除了 1 分及 9 分之外，各分数的范围也是半个标准差。

以下是标准九分及对应的Z-分数，百分位数及占整体比例。

Stanine (STAndard NINE) is a method of scaling test scores on a nine-point standard scale with a mean of five and a standard deviation of two.

Some web sources attribute stanines to the U.S. Army Air Forces during World War II. Psychometric legend has it that a 1-9 scale was used because of the compactness of recording the score as a single digit but Thorndike claims that by reducing scores to just nine values, stanines "reduce the tendency to try to interpret small score differences (p. 131)". The earliest known use of stanines was by the U.S. Army Air Forces in 1943.