同源重组（英语：Homologous recombination）是遗传重组的一种类型，指两股具有相似串行的DNA的重新排列，使遗传物质发生交换。可发生于自然界中，或应用于人工的分子生物学技术。

真核生物体内的同源重组过程中发生于减数分裂时期，是染色体互换所造成的结果。除此之外，同源重组也能使遭受损害的染色体，得以利用与自身相似，且未受伤害的另一条染色体，来进行DNA修复作用。细菌的同源重组，则发生于细菌进行接合（conjugation）、转导（transduction）或是转化（transformation）的过程中。

Homologous recombination is a type of genetic recombination in which nucleotide sequences are exchanged between two similar or identical molecules of DNA. It is most widely used by cells to accurately repair harmful breaks that occur on both strands of DNA, known as double-strand breaks. Homologous recombination also produces new combinations of DNA sequences during meiosis, the process by which eukaryotes make gamete cells, like sperm and egg cells in animals. These new combinations of DNA represent genetic variation in offspring, which in turn enables populations to adapt during the course of evolution. Homologous recombination is also used in horizontal gene transfer to exchange genetic material between different strains and species of bacteria and viruses.