Luísa Rosa de Aguiar Todi (9 January 1753–1 October 1833) was a popular and successful Portuguese mezzo-soprano opera singer.

After their marriage, on her husband's advice, she began having singing lessons with David Perez, an Italian composer and Music Master of the Portuguese Royal Chapel.

In 1770, she began her career as a singer with Giuseppe Scolari's opera Il Viaggiatore Ridicolo, in the Theatre of Bairro Alto.

In 1778 she sang at the famous Concerts Spirituels in Paris, winning a triumph and being considered the best foreign singer ever featured in France.

She returned to Paris for further Concerts Spirituels series, during which time a confrontation arose between Luísa Todi and the German soprano Gertrud Elisabeth Mara (1749–1833), which divided the public.

At the end of that year, she travelled to Venice and performed at the Teatro San Samuele in the opera La Didone Abbandonata, wearing a tiara, necklace, and diamond earrings that had been given to her by the Russian Empress.

Sadly, her native country failed to recognize Luísa's outstanding talent, because her performance was not widely advertised and the Royal Family was absent from the event.

Luísa Todi and her family were imprisoned by the French, but General Soult recognized her as "the Nation's Singer" and protected her.

In spite of constant requests made by Todi enthusiasts and family descendants, one of the greatest Portuguese singers of all time remains buried beneath the pavement of an obscure cellar.

Before her death, Luísa Todi saw her talent immortalised in Antoine Reicha's book Traité de melodie, where she is described as "the Singer of all Centuries".

Todi was praised for her vocal abilities, her clear diction, her linguistic skills (she spoke excellent French, English, Italian, and German), her professionalism, her talent as an actress, and the emotion and sensibility with which she infused her roles – qualities that make her seem an extremely modern performer.