智力商数（德语：Intelligenz Quotient），简称智商（德语：IQ），是用标准测试测量人在其年龄段的认知能力（“智力”）的得分。人的智商呈正态分布，,目前主流的智力测验(包含最常被使用的「魏氏智力测验」)，都采用「离差智商」(deviant IQ scores)的定义。亦即，个体的IQ分数，会和个体所属的常模(例如:和相同年龄、国家的人们)相比较。这个常模的IQ分数的平均值为100分，标准差为15分。即68.2%的人的智商在85-115之间，即95.4%的人的智商在70-130之间, 即99.6%的人的智商在55-145之间。

An intelligence quotient (IQ) is a total score derived from one of several standardized tests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term Intelligenzquotient, his term for a scoring method for intelligence tests he advocated in a 1912 book. When current IQ tests are developed, the median raw score of the norming sample is defined as IQ 100 and scores each standard deviation (SD) up or down are defined as 15 IQ points greater or less, although this was not always so historically. By this definition, approximately two-thirds of the population scores between IQ 85 and IQ 115. About 5 percent of the population scores above 125, and 5 percent below 75.