Lawrence Justinian (Italian: Lorenzo Giustiniani, 1 July 1381 – 8 January 1456) was a Venetian Catholic priest and bishop who became the first Patriarch of Venice.

In 1404, after he had been ordained a deacon, at the suggestion of an uncle who was a priest, he joined a community of canons regular following a monastic form of life on the island of San Giorgio in Alga.

Due to their centuries of close trading partnerships with Byzantine Empire, the people of Venice were in panic as to their future.

[7] Pope Innocent XII (1691–1700) inserted his feast day in the General Roman Calendar for celebration on 5 September, the anniversary of his elevation to the episcopate.

Because of the saint's limited importance worldwide, his liturgical celebration is no longer included in the General Roman Calendar,[8] and his feast was moved to 8 January, the day of his death.