超几何分布是统计学上一种离散概率分布。它描述了由有限个对象中抽出n个对象，成功抽出指定种类的对象的个数（不归还）。

例如在有N个样本，其中m个是不及格的。超几何分布描述了在该N个样本中抽出n个，其中k个是不及格的机率：

上式可如此理解：表示所有在N个样本中抽出n个的方法数目。 表示在m个样本中，抽出k个的方法数目，即组合数，又称二项式系数。剩下来的样本都是及格的，而及格的样本有N-m个，剩下的抽法便有种。

若n=1，超几何分布还原为伯努利分布。

若N接近∞，超几何分布可视为二项分布。

例子：

Now, assume (for example) that there are 5 green and 45 red marbles in the urn. Standing next to the urn, you close your eyes and draw 10 marbles without replacement. What is the probability that exactly 4 of the 10 are green? Note that although we are looking at success/failure, the data are not accurately modeled by the binomial distribution, because the probability of success on each trial is not the same, as the size of the remaining population changes as we remove each marble.