Andreas Musculus (also Andreas Meusel; 29 November 1514 – 29 September 1581) was a German Lutheran theologian and Protestant reformer. The name Musculus is a Latinized form of Meusel.
Musculus was born in Schneeberg, "generally called only Musculus" and educated in Leipzig and Wittenberg. He became professor at the university of Frankfurt an der Oder. As a theologian he was Gnesio-Lutheran and wrote polemics against the Interim, Andreas Osiander the Elder, Franciscus Stancarus, Philipp Melanchthon and John Calvin.
Musculus was one of the co-authors of the Formula of Concord. He was also one of the most remarkable defenders of Eucharistic adoration in early Lutheranism. His main work on this subject is Propositiones de vera, reali et substantiali praesentia, Corporis & Sanguinis IESU Christi in Sacramento Altaris, Francofordiae ad Oderam, 1573 (thesis IX: An adoratio Christi praesentis in coena sit approbanda). He also edited prayer books with the classical hymns for the adoration of the Sacrament . E.g. his Precationes ex veteribus orthodoxis included Lauda Sion and Pange lingua. He died in Frankfurt an der Oder.