2004年印度洋大地震（一般简称印度洋海啸或南亚海啸，科学界称为苏门答腊－安达曼地震）发生于2004年12月26日当地时间（雅加达、曼谷）UTC+7上午7时58分55秒，震央位于印尼苏门答腊岛西160千米，水下3千米深处，矩震级达到9.3。印度洋大地震是继1960年智利大地震（9.5级）以及1964年阿拉斯加耶稣受难日地震（9.2级）之后的又一次强震，也是1900年以来规模第二大的地震。它引发了高达三十余公尺的海啸，波及范围远至波斯湾的阿曼、非洲东岸索马里及毛里求斯、留尼旺等国，地震及震后海啸对东南亚及南亚地区造成巨大伤亡，死亡和失踪人数超过29万余人。

The 2004 Indian Ocean earthquake occurred at 00:58:53 UTC on 26 December with the epicentre off the west coast of Sumatra, Indonesia. The shock had a moment magnitude of 9.1–9.3 and a maximum Mercalli intensity of IX (Violent). The undersea megathrust earthquake was caused when the Indian Plate was subducted by the Burma Plate and triggered a series of devastating tsunamis along the coasts of most landmasses bordering the Indian Ocean, killing 230,000 people in 14 countries, and inundating coastal communities with waves up to 30 metres (100 ft) high. It was one of the deadliest natural disasters in recorded history. Indonesia was the hardest-hit country, followed by Sri Lanka, India, and Thailand.