Jean-Marie Leclair l'aîné, also known as Jean-Marie Leclair the Elder, (10 May 1697 – 22 October 1764) was a Baroque violinist and composer. He is considered to have founded the French violin school. His brothers Jean-Marie Leclair the younger (1703–77), Pierre Leclair (1709–84) and Jean-Benoît Leclair (1714–after 1759) were also musicians.
Leclair was born in Lyon, but left to study dance and the violin in Turin. In 1716, he married Marie-Rose Casthanie, a dancer, who died about 1728. Leclair had returned to Paris in 1723, where he played at the Concert Spirituel, the main semi-public music series. His works included several sonatas for flute and basso continuo.
In 1730, Leclair married for the second time. His new wife was the engraver Louise Roussel, who prepared for printing all his works from Opus 2 onward. Named ordinaire de la musique by Louis XV in 1733, Leclair resigned in 1737 after a clash with Guidon over control of the musique du Roy.
Leclair was then engaged by the Princess of Orange – a fine harpsichordist and former student of Handel – and from 1738 until 1743, served three months annually at her court in Leeuwarden, working in The Hague as a private maestro di cappella for the remainder of the year. He returned to Paris in 1743. His only opera Scylla et Glaucus was first performed in 1746 and has been revived in modern times. From 1740 until his death in Paris, he served the Duke of Gramont, in whose private theatre at Puteaux were staged works to which Leclair is known to have contributed. They included, in particular, a lengthy divertissement for the comedy Les danger des épreuves (1749) and one complete entrée, Apollon et Climène, for the opéra-ballet by various authors, Les amusemens lyriques (1750).