Manuel Pereira de Sampaio (Lagos; 1692 - Rome; February 1750) was a Portuguese nobleman and diplomat, who served as King John V of Portugal's ambassador to the Holy See.

[2] While ambassador, Pereira de Sampaio cataloged the numerous artistic commissions made by King John V in Rome, including artwork destined for Ribeira Palace and the famed Chapel of St. John the Baptist, destined for the Igreja de São Roque, in what is now known as the Weale Album.

On 15 September 1742, by consideration of services made at the court of Rome, Manuel Pereira de Sampaio, asked for a letter of confirmation of the commandery of Santo António, of the Order of Christ and of the presentation of the House of Bragança, by abandonment of Manuel Caetano Lopes.

[1] In 1748, Pereira de Sampaio achieved what is considered as the high point of his career, the granting of the style Most Faithful Majesty, by Pope Benedict XIV to King John V. Pereira de Sampaio died in February 1750, in Civitavecchia, of an asthma attack, while preparing for an expedition back to Lisbon with works of art destined for the Patriarchal Basilica in Lisbon.

He is buried in Sant'Antonio dei Portoghesi with a funerary monument dedicated to him designed by Filippo Della Valle.