Guglielmo Quarenghi (October 22, 1826 – February 3, 1882) was an Italian composer and cellist. From 1839 to 1842 he studied with at the Milan Conservatory. In 1850 he became principal cellist at La Scala, and in 1851 a professor at the conservatory. Along with Luigi Felice Rossi and Alberto Mazzucato, Quarenghi formed the Società di S Cecilia in 1860. In 1879 he succeeded Raimondo Boucheron as maestro di cappella of Milan Cathedral. He resigned two years later due to ill-health and died in 1882.