奥斯曼·伊本·阿凡（阿拉伯文：عثمان بن عفان‎ ， 574年~656年6月17日），为伊斯兰教历史上的的第三任哈里发（644年~656年在位）。逊尼派认为他是四位“正统哈里发”中的一位；而什叶派则认为他与前两位哈里发一样都是篡权者。

奥斯曼·伊本·阿凡出身于麦加古来氏族中的倭马亚家族，年纪比先知穆罕默德略小。在以兄长阿布·苏富扬为代表的大部分倭马亚家族成员激烈反对穆罕默德传布伊斯兰教时，奥斯曼却是穆罕默德最初的信徒和最亲密的战友之一。奥斯曼迎娶了穆罕默德的两个女儿。当穆罕默德被迫离开麦加后，奥斯曼和妻子参加了伊斯兰教徒向埃塞俄比亚的移民（当时移民的穆斯林家庭共有十五个），以及后来向麦地那的移民。

Uthman ibn Affan (Arabic:عثمان بن عفان‎, translit. ‘Uthmān ibn ‘Affān; also known in English by the Turkish and Persian rendering Osman; 576 – 17 June 656) was a companion of the Islamic prophet Muhammad, and the third of the Rashidun or "Rightly Guided Caliphs". Born into a prominent Meccan clan of the Quraysh tribe, he played a major role in early Islamic history, succeeding Umar ibn al-Khattab as caliph at age 65. He was also the prophet's son-in-law twice, being married to two of the prophet’s daughters Ruqayyah and Umm Kulthum (he was married to the second daughter after the first passed away).