Carlos Mardel (born Martell Károly; Pressburg; c. 1695 – Lisbon; 8 September 1763) was a Hungarian-Portuguese military officer, engineer, and architect.

[3] It is known that Mardel was a part of the Portuguese Freemason lodge Casa Real dos Pedreiros Livres da Lusitânia, which operated between 1733 and 1738.

[3] In 1747, owing to his work on the Águas Livres water system, Mardel was appointed Architect of the Royal Household and of the Ancient Military Orders.

Following the 1755 Lisbon earthquake, Mardel was one of the primary architects responsible for the city's reconstruction, alongside Eugénio dos Santos and Manuel da Maia.

[3] In 1759, Mardel began construction on a country manor in Oeiras for Sebastião José de Carvalho e Melo, the prime-minister at the time for King Joseph I of Portugal.