Sebastiano Conca (8 January 1680 – 1 September 1764) was an Italian painter.
He was born at Gaeta, then part of the Kingdom of Naples, and apprenticed in Naples under Francesco Solimena. In 1706, along with his brother Giovanni, who acted as his assistant, he settled in Rome, where for several years he worked only in chalk, to improve his drawing. He was patronized by the Cardinal Ottoboni, who introduced him to Clement XI, who commissioned him a well-received Jeremiah painted for the church of St. John Lateran. He also painted an Assunta for the church of Santi Luca e Martina in Rome.
Conca was knighted by the pope. He collaborated with Carlo Maratta in the Coronation of Santa Cecilia(1721–24) in the namesake church of Santa Cecilia in Trastevere. In 1718 He was elected to the Accademia di San Luca, and was its director in 1729-1731, replacing Camillo Rusconi as Principe in 1732. He was also elected Principe in 1739-1741.
His painting was strongly influenced by the Baroque painter Luca Giordano. Among Conca's pupils there were Pompeo Battoni, Andrea Casali, Placido Campoli, Corrado Giaquinto, Gregorio Giusti,Gaetano Lapis, Salvatore Monosilio, Litterio Paladini,Francesco Preziao, Rosalba Maria Salvioni, Gasparo Serenari, Agostino Masucci,Domenico Giomi, and the Bavarian religious painter Franz Georg Hermann. Sebastiano's brother, Giovanni Conca (died in 1764), painted the main altarpiece of the Madonna of the Rosary and St Dominic for the church of San Domenico, Urbino.