杂种优势（Heterosis）是一个用在遗传学和育种之上的术语。杂种优势是指杂交种通过继承其父母的不同的优势，可能获得一个更好的生物特性（但是也可能杂交后只继承了父母各自的缺点导致变得更差）。

杂种优势一般和近交衰退相对比。

相对的也有远交衰退，如杂种衰败，杂种由于生殖隔离等原因不能产生后代。

Heterosis, hybrid vigor, or outbreeding enhancement, is the improved or increased function of any biological quality in a hybrid offspring. The adjective derived from heterosis is heterotic.

An offspring exhibits heterosis if its traits are enhanced as a result of mixing the genetic contributions of its parents. These effects can be due to Mendelian or non-Mendelian inheritance.