Giovanni Battista Fontana (ca.1580/89 - ca.1630) was an Italian [Baroque] composer and violinist.
He was born in Brescia, and worked there and in Rome and Padova. He died in Padova during a plague.
Nearly all information preserved about him comes from the preface of his posthumously published 18 (sometimes incorrectly stated 12) sonatas (Sonate a 1.2.3. per il violino, o cornetto, fagotto, chitarone, violoncino o simile altro istromento, Venice, 1641). They are among the earliest sonatas of this form, consisting of 6 sonatas for solo violin/cornetto with continuo and 12 sonatas for one to three violins and continuo, the latter group often including a demanding concertante part for bassoon or cello. An "atto di morte" dated 7 September 1630 for a “Zan Batta Fontana” aged 50, is the only one among the Paduan death registers of 1625–30 for a person bearing that name.