Buenaventura (Ventura) Cousiño Jorquera (1808–1855) was a Chilean congressman, lawyer and politician.

He studied at the National Institute and graduated as a lawyer from the faculty of law at the San Felipe University in 1836.

He conducted Latin classes at the National Institute and in 1845 he joined the Faculty of Philosophy and Humanities at the University of Chile, where he delivered a speech on "Excellence in Latin literature", a work that was published in the Annals of the University.

During this time he joined the Standing Committee on Government, Foreign Affairs and Education and Charities.

He was Deputy of Melipilla, in 1849, working on the Standing Committee on Constitution, Law and Justice, and Government and Foreign Affairs.