Luísa Margarida de Barros Portugal (13 April 1816 – January 1891), later Countess of Barral, was a Brazilian noble and courtier, preceptor of Brazilian princesses Isabel and Leopoldina, rumored to be the major love interest of Pedro II of Brazil and later part of Louis Philippe I of France's court.

She was the daughter of the Brazilian diplomat and noble Domingos Borges de Barros, the viscount of Pedra Branca, statesman of the first reign, and his wife Maria do Carmo Gouveia Portugal, descendant of traditional families of New Christians of Bahia and the last rabbi of Spain before inquisition, Dom Abraham Senior, according to genealogist Francisco Antonio Doria, in the book "Herdeiros do Poder" and the work "The Occult Rabbi - the saga of a family by Jewish origin - by Carmen Nogueira".

She was also named lady-in-waiting to Teresa Cristina in September 1855, although the real companion of the empress was Josefina da Fonseca Costa.

Luísa Margarida immediately set about establishing her authority in the palace, a place where power was hotly contested, and for that reason caused the fury of many of the more self-serving officials.

The Emperor met his friend on the two trips he undertook to Europe, in 1870 and 1887, and in the last months of his life, when, a widower and exiled, he spent some time at the Countess's residence in Cannes.

In the 1940s, the Count of Barral, his grandson, donated to the Imperial Museum of Petrópolis the letters exchanged between his grandmother and the Emperor of Brazil, which show the relationship between them.