Lorenzo María Alier Cassi (1878–1942) was a Spanish Catalan lawyer and politician. In jurisprudence he is known as author and co-author of few encyclopedic works and as dean of the Barcelona Colegio de Abogados in 1939-1942. In politics he remained a Carlist throughout all his life. His career climaxed twice; in 1907-1910 he served one term in the lower chamber of the Cortes, and in 1934-1936 he was leader of the regional Catalan branch of the Carlist organization, Comunión Tradicionalista.