奥斯伍尔德·西奥多·埃弗里（Oswald Theodore Avery，1877年10月21日－1955年2月2日）生于加拿大新斯科舍省哈利法克斯，美国医生、最早的分子生物学家之一、免疫化学先驱，曾长期在纽约市洛克菲勒研究院附属医院工作。埃弗里最大成就是1944年与科林·麦克劳德和麦克林恩·麦卡蒂共同发现脱氧核糖核酸（DNA）是染色体的主要成分及构成基因的主要材料。

1955年逝世于田纳西州纳什维尔。

为了纪念他的贡献，月球上的一个环形山被命名为埃弗里。

Oswald Theodore Avery Jr. FRS (October 21, 1877 – February 20, 1955) was a Canadian-born American physician and medical researcher. The major part of his career was spent at the Rockefeller University Hospital in New York City. Avery was one of the first molecular biologists and a pioneer in immunochemistry, but he is best known for the experiment (published in 1944 with his co-workers Colin MacLeod and Maclyn McCarty) that isolated DNA as the material of which genes and chromosomes are made.