Julián Baltasar Mariano José Luis de la Santísima Trinidad Álvarez (Buenos Aires, 8 January 1788 – Montevideo, 25 November 1843) was an Argentine and Uruguayan lawyer and politician.

Julián Álvarez studied at the Real Colegio de San Carlos later attending the University of Charcas, where he obtained a law degree.

After the defeat, exile and death of Mariano Moreno, he headed the "Sociedad Patriótica", the most liberal political group in Buenos Aires.

When the province seceded from Argentina and Brazil to become Uruguay, he was a member of the Constitutional Congress of the new country for San José de Mayo (1830).

During the Uruguayan Civil War, he was a member of the Gobierno de la Defensa, and was three times President of the Chamber of Deputies of Uruguay from 1841 to 1843.

His daughter Amelia married the medical doctor and Argentine politician Ireneo Portela while he was in exile in Uruguay and Julián Álvarez was still alive.