Most of its electorate is formed by so-called "bevindelijk gereformeerden", Reformed Christians for whom personal religious experience is very important.
The SGP's support is concentrated geographically in the Dutch bible belt, a band of strongly Reformed municipalities ranging from Zeeland in the South via Goeree-Overflakkee and the Alblasserwaard in South Holland and the Veluwe in Gelderland to the Western part of Overijssel, around Staphorst.