约翰·米尔顿·海伊（John Milton Hay，1838年10月8日 - 1905年7月1日），又译海约翰，美国印地安那州华盛顿郡人，作家、记者、外交家、政治家，曾任林肯总统私人秘书，后于威廉·麦金莱和老罗斯福等总统时期任国务卿。

在对华事务方面，反对列强划分势力范围，主张「门户开放政策」，要求「中国开户开放，各国利益均沾」，从而避免了瓜分中国。清光绪三十年至三十一年（1904至1905年清光绪三十年至三十一年），认为庚子赔款赔款过多，希望减免。大清驻美公使梁诚从中斡旋，促成减免。美国总统罗斯福决定返还赔款基数定为一千余万美元，逐年退还。赔款用于人才培养和赴美留学。

John Milton Hay (October 8, 1838 –July 1, 1905) was an American statesman and official whose career in government stretched over almost half a century. Beginning as a private secretary and assistant to Abraham Lincoln, Hay's highest office was United States Secretary of State under Presidents William McKinley and Theodore Roosevelt. Hay was also an author and biographer, and wrote poetry and other literature throughout much of his life.