Giovanni Merlini (28 August 1795 - 12 January 1873) was an Italian Roman Catholic priest and a professed member in the Missionaries of the Precious Blood.
Merlini was a close friend of Saint Gaspare del Bufalo who founded the order and was also a close friend to Pope Pius IX who provided assistance in helping the order spread for its activities.
He also served as the third Moderator General for the order from 1847 until his death.
He was also a noted spiritual director and provided spiritual counsel to Saint Maria de Mattias as she went establishing a religious congregation of her own.The beatification process for Merlini opened in the 1880s in Rome and took several decades to complete.
In 1973 he became titled as Venerable after Pope Paul VI confirmed that the late priest had practiced heroic virtue during his lifetime.