Louis William Wain was an English artist best known for his drawings of anthropomorphised cats and kittens.

Wain was born in Clerkenwell, London. In 1881 he sold his first drawing and the following year gave up his teaching position at the West London School of Art to become a full-time illustrator. He married in 1884 but was widowed three years later. In 1890 he moved to the Kent coast with his mother and five sisters, and, except for three years spent in New York, remained there until the family returned to London in 1917. In 1914, he suffered a severe head injury in an omnibus accident and ten years later was certified insane. He spent the remaining fifteen years of his life in mental hospitals, where he continued to draw and paint. Some of his later abstract paintings have been seen as precursors of psychedelic art.

Wain produced hundreds of drawings and paintings a year for periodicals and books, including Louis Wain's Annual which ran from 1901 to 1921. His work also appeared on postcards and advertising, and he made brief ventures into ceramics and animated cartoons. In spite of his popularity and prolific output, Wain did not become wealthy, possibly because he sold his work cheaply and relinquished copyright, and also because he supported his mother and five sisters.