邻接矩阵是表示一个图的常用存储表示。它用两个数组分别存储数据元素（顶点）的信息和数据元素之间的关系（边或弧）的信息。

距离矩阵可算是邻接矩阵的扩充。

阶为的图的邻接矩阵是的。将的顶点标签为。若，，否则。

无向图的邻接矩阵是对称矩阵。

In graph theory, computer science and application areas such as sociology, an adjacency matrix is a square matrix used to represent a finite graph. The elements of the matrix indicate whether pairs of vertices are adjacent or not in the graph.

In the special case of a finite simple graph, the adjacency matrix is a (0,1)-matrix with zeros on its diagonal. If the graph is undirected, the adjacency matrix is symmetric. The relationship between a graph and the eigenvalues and eigenvectors of its adjacency matrix is studied in spectral graph theory.