Portrait of Charles Frederick is a 1738 portrait painting by the Italian artist Andrea Casali. It depicts the British politician Charles Frederick. Painted in Rome, it is a significant early example of the Grand Tour portrait style that became an established tradition for British visitors in Italy during the eighteenth century. He is shown seated at a table in a curtained loggia with the Pantheon in the background, and has the composition of what would become the standard Neoclassical portrait. He is shown seated at a table Stylistically it provides a bridge between Francesco Trevisani and Pompeo Batoni.
Frederick was a noted antiquarian, who travelled to Italy with his brother in 1737-38. He became a significant patron to Casali when he relocated to England in 1741. Today the painting is in the collection of the Ashmolean Museum in Oxford, having been acquired in 1980.