Santissimo Sacramento in San Giovanni della Malva was an oratory, now demolished, on the north side of Piazza di San Giovanni della Malva in Trastevere.
The parish of San Giovanni della Malva in Trastevere was prosperous enough in the early 18th century to have an important Eucharistic confraternity, the Confraternita del Santissimo Sacramento dei Santi Giovanni Battista e Giovanni Evangelista della Malva a Trastevere. They built a separate oratory for itself on the piazza on which the parish church stood, and this was large enough to amount to a small church.
The oratory appears on the Nolli map of 1748, and a Vasi engraving shows it as part of a larger domestic building without a distinctive façade except for an oversized entrance doorway. The plan was rectangular, with a small presbyterium separated by a triumphal arch.
The oratory was at the east end of the block occupying the north side of the piazza, and took up the entire west side of the little street leading to the Vicolo Moroni.