Mass Giorgini is an American rock musician. The son of renowned artist Aldo Giorgini, he has played bass in some of the formative bands of the pop punk genre. He began his musical career as bassist of the band Rattail Grenadier. He is one of the founding members of Squirtgun, a band with which he continues to play.

Mass has also played bass in Screeching Weasel and Common Rider, and for a short time also played bass guitar with Ben Weasel's band, Sweet Black And Blue. In addition, Mass Giorgini is a saxophonist, playing not only in Common Rider, but also as a guest on albums by several other bands, including Moral Crux and Scarred Hope.

Perhaps more notable than his endeavors as a musician are his credits for his work on the production of punk recordings. As a producer, he has worked in conjunction with leading punk rock figures such as Billie Joe Armstrong of Green Day and Kris Roe of the Ataris, as well as assisting noted producers such as Paul Mahern (John Mellencamp, Iggy Pop), John Strohm (Lemonheads, Blake Babies), and Anjali Dutt (Oasis, Swervedriver). Since 1990, he has owned and operated Sonic Iguana Studios in Lafayette, Indiana. He has had his hands in creating the recordings of many bands (sometimes recording, mixing, mastering, and producing).