The Lex Baiuvariorum (also Lex Baiuwariorum, Lex Bajuvariorum, or Lex Baivariorum) was a collection of the tribal laws of the Bavarii of the sixth through eighth centuries. The first compilation was edited by Eberswind, first abbot of Niederaltaich, in 741 or 743. Duke Odilo, founder supplemented the code around 748. It is one of the most well documented bodies of Germanic tribal law.
Parts of the Lex Baiuvariorum are identical with the Visigothic Code of Euric and from the Lex Alamannorum. The Bavarian law, therefore, is later than that of the Alamanni. It dates unquestionably from a period when the Frankish authority was very strong in Bavaria, when the dukes were vassals of the Frankish kings. Immediately after the revolt of Bavaria in 743, the Bavarian Duke Odilo was forced to submit to Pippin the Younger and Carloman, the sons of Charles Martel, and to recognize the Frankish suzerainty. About the same period, too, the church of Bavaria was organized by St Boniface, and the country divided into several bishoprics; and we find frequent references to these bishops (in the plural) in the law of the Bavarians. On the other hand, we know that the law is anterior to the reign of Duke Tassilo III (749-788). The date of compilation must, therefore, be placed between 743 and 749.
Wilhelm Störmer claims that though the Lex Baiuvariorum uses some identical titles as Visigothic and Alamani texts, synodal texts and the Tradition Book of Freising indicate that it cannot simply be a copy. K. Reindels claims that the law could have been developed in stages, starting with the reign of Theudebert I (539–548) until we have the version that we know today created during the reign of Odillo. What is certain is that the Lex Baiuvariorum was created at the behest of the Frankish overlords.