阿尔弗雷德·伟格纳（Alfred Lothar Wegener，1880年11月1日－1930年11月2日）是一位德国地质学家、气象学家、天文学家。阿尔弗雷德·魏格纳是大陆漂移说创立者，该学说认为远古时代的地球只有一块「泛古陆」或称盘古大陆的庞大陆地，被称为「泛大洋」的水域包围，该大陆后来开始破裂，形成现在的七大洲和五大洋的基本地貌。其他汉语译名主要有“艾尔弗雷德·魏格纳”、“阿尔弗里德·威格纳”、“阿鲁夫雷多·魏格纳”、“艾尔弗雷德·韦格纳”，简称“魏格纳”。

魏格纳起初研究天文学及气象学，喜爱冒险，曾乘坐热气球参加耐空比赛，并曾经以52小时的成绩打破当时最长的耐空纪录（35小时）。他在第一次世界大战时曾参军并两度负伤。魏格纳留意到非洲大陆西岸和南美洲东岸的海岸线很相似，因此推测大陆原本是相连的，1912年1月在德国法兰克福举行的地质研讨会首次提出大陆漂移的观点，1915年正式出版《大陆与大洋的起源》一书。他曾四次前往格陵兰进行极地上层大气及冰河学的研究及探险活动，并曾在北纬77度的冰上连续渡过两个冬天。1930年11月，在最后一次前往格陵兰的探险中死亡，享年50岁。魏格纳也是提出柯本气候分类法的气象学家弗拉迪米尔·彼得·柯本的女婿。

Alfred Lothar Wegener (1 November 1880 – November 1930) was a German polar researcher, geophysicist and meteorologist.

During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered as the originator of the theory of continental drift by hypothesizing in 1912 that the continents are slowly drifting around the Earth (Kontinentalverschiebung). His hypothesis was controversial and not widely accepted until the 1950s, when numerous discoveries such as palaeomagnetism provided strong support for continental drift, and thereby a substantial basis for today's model of plate tectonics. Wegener was involved in several expeditions to Greenland to study polar air circulation before the existence of the jet stream was accepted. Expedition participants made many meteorological observations and achieved the first-ever overwintering on the inland Greenland ice sheet as well as the first-ever boring of ice cores on a moving Arctic glacier.