《吐蕃大事纪年》（藏语：.mw-parser-output .uchen{font-family:"Qomolangma-Dunhuang","Qomolangma-Uchen Sarchen","Qomolangma-Uchen Sarchung","Qomolangma-Uchen Suring","Qomolangma-Uchen Sutung","Qomolangma-Title","Qomolangma-Subtitle","Qomolangma-Woodblock","DDC Uchen","DDC Rinzin",Kailash,"BabelStone Tibetan",Jomolhari,"TCRC Youtso Unicode","Tibetan Machine Uni",Wangdi29,"Noto Sans Tibetan","Microsoft Himalaya"}.mw-parser-output .ume{font-family:"Qomolangma-Betsu","Qomolangma-Chuyig","Qomolangma-Drutsa","Qomolangma-Edict","Qomolangma-Tsumachu","Qomolangma-Tsuring","Qomolangma-Tsutong","TibetanSambhotaYigchung","TibetanTsugRing","TibetanYigchung"}དོན་ཆེན་གནད་བསྔུས་ཀྱི་ལོ་ཚིགས།，英语：Old Tibetan Annals），简称《大事纪年》，是敦煌莫高窟藏经洞中发现的一部藏文文献。该书于11世纪左右被封存于莫高窟17号藏经洞，于20世纪初期被探险家伯希和发现。

这部史书记载了吐蕃帝国时期的许多历史大事，可以弥补藏文传统史书记载上的不足。分为内政和军事两部分，其中内政部分记载了吐蕃自650年至748年期间的内政事务，军事部分记载了743年至765年期间的一些大的战事。现分别藏于大英博物馆和法国国家图书馆。