基因改造生物 (英语：Genetically Modified Organism, GMO)，或称转基因生物、遗传修饰生物体，是指通过基因改造实现基因改变的生物。这种技术，通常称作重组DNA技术。在生成转基因生物的一般原理是，将新的遗传物质添加到一个生物体内的基因。这就是基因工程，并通过DNA被发现，这称作基因工程，在DNA的发现成为可能。

基因改造食物，便是利用基因工程将原有食物的基因加入其他生物的遗传物质，并将不良基因移除，从而造成品质更好的食物。通常基因改造食物，可增加食物的产量、抗寒及其他特性。然而，基因改造食物的风险，例如基因污染问题也不能忽视。

A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques (i.e., a genetically engineered organism). GMOs are the source of medicines and genetically modified foods and are widely used in scientific research and to produce other goods. The term GMO is very close to the technical legal term, 'living modified organism', defined in the Cartagena Protocol on Biosafety, which regulates international trade in living GMOs (specifically, "any living organism that possesses a novel combination of genetic material obtained through the use of modern biotechnology").