Lush, colorful flower and fruit still lifes were Jan van Os' specialty. In the 18th century he was the leading pronk still life painter with Jan van Huysum. He was also known for his seascapes, which are often from an earlier date than the still lifes. From 1773 to 1791, Van Os also sent his work to the Society of Artists in London, making his paintings much sought after by the English aristocracy. Jan van Os' children were also talented artists: eldest son Pieter Gerardus painted animals and landscapes, second son Georgius Jacobus Johannes and daughter Maria Margaretha specialized in still lifes.