关联性磁振频谱（Correlation spectroscopy, COSY）是二维核磁共振（NMR）频谱学中的一种技术，其他二维NMR技术包括有J频谱（J-spectroscopy）、交换谱（Exchange spectroscopy, EXSY）及核欧佛豪瑟效应频谱（Nuclear Overhauser effect spectroscopy, NOESY）。二维NMR频谱对于分子提供了比一维NMR频谱更多的信息，在对分子结构的决定上极为有用，尤其当分子极为复杂，难以用一维NMR来研究之时。历史上第一项二维NMR实验方法——COSY是由Jean Jeener于1971年首先提出，其为布鲁塞尔自由大学（Université Libre de Bruxelles）教授。真正的实验由Walter P. Aue、Enrico Bartholdi 及理乍得·恩斯特（Richard R. Ernst）三人首先完成，于1976年发表。

Two-dimensional nuclear magnetic resonance spectroscopy (2D NMR) is a set of nuclear magnetic resonance spectroscopy (NMR) methods which give data plotted in a space defined by two frequency axes rather than one. Types of 2D NMR include correlation spectroscopy (COSY), J-spectroscopy, exchange spectroscopy (EXSY), and nuclear Overhauser effect spectroscopy (NOESY). Two-dimensional NMR spectra provide more information about a molecule than one-dimensional NMR spectra and are especially useful in determining the structure of a molecule, particularly for molecules that are too complicated to work with using one-dimensional NMR.