Stefano Maria Legnani also known as "Legnanino" was an Italian painter of the late Baroque period, active mainly in Milan. He is considered one of the most innovative exponents of the Milanese school of painting of around the turn of the 17th and 18th centuries.

Legnanino was born in Milan as the first born son of the painter Giovanni Ambrogio Legnani and Isabella Bussola. His grandfather Tommaso Legnani was also a painter.

Legnanino likely received his first art training with his father. It has been conjectured that subsequently he went on to work in the studio of Carlo Cignani in Bologna from 1683 to 1686, and then apprenticed with Carlo Maratta in Rome. However, neither of these apprenticeships are confirmed by documentation.

On 30 October 1694 the artist married Caterina Sanpietro, with whom he had three daughters. In that year he also received an important commission from Count Ottavio Provana di Druent to paint a series of celebratory frescoes in his residence, today known as Palazzo Falletti Barolo. The works he realised there established his reputation and were instrumental in him obtaining in 1695 a very prestigious commission to create the fresco decorations for the new palace of Emmanuel Philibert, Prince of Carignano. This palace had been designed by Guarino Guarini.