O Primo Basílio ("Cousin Bazilio") is one of the most highly regarded realist novels of the Portuguese author José Maria de Eça de Queiroz. He worked in the Portuguese consular service in Newcastle upon Tyne from late 1874 until April 1879. The novel was written during this productive period in his career, appearing in 1878.

A bowdlerized translation of this book by Mary Jane Serrano under the title Dragon's Teeth: A Novel was published in the United States in 1889. More accurate translations have since been published, first in 1953 by the poet Roy Campbell and then in 2003 by award-winning translator Margaret Jull Costa.

O Primo Basílio é um romance de Eça de Queiroz. Publicado em 1878, constitui uma análise da família burguesa urbana no século XIX.

O autor, que já criticara a província em O Crime do Padre Amaro, volta-se agora para a cidade, a fim de sondar e analisar as mesmas mazelas, desta vez na capital: para tanto, enfoca um lar burguês aparentemente feliz e perfeito, mas com bases falsas e igualmente podres.