| Order: | 120th Doge of the Republic of Genoa |
| Term Start1: | April 6, 1611 |
| Term End1: | April 6, 1613 |
| Predecessor1: | Agostino Pinelli Luciani |
| Successor1: | Tomaso Spinola |
| Birth Date: | 1554 |
| Birth Place: | Genoa, Republic of Genoa |
| Death Date: | 1631 |
| Death Place: | Genoa, Republic of Genoa |
Alessandro Giustiniani Longo (Genoa, 1554 – Genoa, 1631) was the 89th Doge of the Republic of Genoa.
Exponent of the so-called "new" nobility, he was elected to the highest dogal position with the elections of April 6, 1611, the forty-fourth in biennial succession and the eighty-ninth in republican history. Of his Dogate are remembered the final negotiations for the acquisition of the city of Sassello. After his Doge's mandate ended on April 6, 1613 he was elected to the office of perpetual prosecutor. He died in the Genoese capital in 1631.[1]