Robert Thegerstrom (1857–1919) was a Swedish visual artist born in London, but active in Stockholm. He studied at the Academy of Fine Arts in Stockholm, arrived in Paris as late as 1880, and would devote himself extensively to plein air painting on the Atlantic coast and in Grez-sur-Loing. He traveled to Paris in 1880, where he spent twelve years studying and practicing his independent art. He studied figure and landscape painting at several reputable studios, including the Académie Julian, where he became familiar with the then-trending salon painting style with realistic plein air studies and figure depictions. With his good finances and social standing, he came to play a significant role among the Swedish artists in Paris. Thegerström was one of the central figures in the social circles at artists' taverns and studios. He was part of the core group of the Opponents. When Thegerström returned to Sweden, he began to depict the Swedish landscape in atmospheric tones, carried out public works and became primarily a portrait painter with bl.a. writer and musician as a model. Thegerström was a close friend of Anders Zorn and was impressed by his plein air painting, which is seen in the famous painting "Lättja". Thegerström married Elin Lamm in 1887, who is believed to be the one depicted in the painting, "Lättja". She was a cousin of Zorn's wife Emma. Thegerström is primarily considered a landscape painter and he painted motifs taken from Djursholm and Särö. He painted portraits, but is also considered a graphic artist. He is represented at the National Museum and Waldemarsudde in Stockholm as well as other Swedish museums.