异速生长（英语：Allometry）是关于身体大小与形状、解剖学、生理学及至行为间关系的研究，于1892年被Otto Snell，1917年被D'Arcy Thompson和1932年被朱利安·赫胥黎首先阐述。异速生长是个著名的研究论题，尤其在统计形状分析及活机体不同部分生长率研究的生物学上。应用之一就是在各种昆虫种类研究上，即整个身体中的某个小部位的变化，能够导致四肢附件如腿、触角等呈现巨大的不成比例的变化。两种不同测量数量间的关系可用下列公式表示：

为公式的标度幂指数。估计此指数可从类型2回归，如主轴回归或压轴回归分析来解释两变量的变化，与最小二乘法回归相反，它不解释自变量（如对数体重）的误差方差。其他方法包括测量误差模型和特别类型的主成分分析法。

Allometry is the study of the relationship of body size to shape, anatomy, physiology and finally behaviour, first outlined by Otto Snell in 1892, by D'Arcy Thompson in 1917 in On Growth and Form and by Julian Huxley in 1932. Allometry is a well-known study, particularly in statistical shape analysis for its theoretical developments, as well as in biology for practical applications to the differential growth rates of the parts of a living organism's body. One application is in the study of various insect species (e.g., the Hercules Beetle), where a small change in overall body size can lead to an enormous and disproportionate increase in the dimensions of appendages such as legs, antennae, or horns. The relationship between the two measured quantities is often expressed as a power law equation: