We utilized resistivity models of silicic magma chambers to explore effects that layering can have on three-dimensional (3-D) magnetotelluric (MT) responses. Model simulations show that MT detection of magma may depend strongly on its one-dimensional host. The 3-D responses of a model juvenile magma body which is connected electrically to deeper, less resistive crust of regional extent are very subdued. However, intermediate and mature magmatic systems, leaving magma no longer in contact with lower, less resistive crust, may be detectable with the MT method. Further, the release and ascent of volatiles from crystallizing melt may lead to fracturing above the chamber, thereby establishing electrical contact of the magma with shallow, conductive crust and amplifying its MT response.