Eugène Fredrik Jansson (18 March 1862, Stockholm – 15 June 1915, Skara) was a Swedish painter known for his night-time land- and cityscapes dominated by shades of blue. Towards the end of his life, from about 1904, he mainly painted male nudes. The earlier of these phases has caused him to sometimes be referred to as blåmålaren, "the blue-painter".

Jansson's parents belonged to a social stratum straddling the working and the lower middle class, but they were interested in art and music and ambitious for their two sons, Eugène and his younger brother Adrian. Eugène went to the German School in Stockholm and took piano lessons. An attack of scarlet fever at the age of fourteen caused him health issues from which he suffered for the res...