This note is an introduction to agenda item GFF/IG3/4, “GFF Financing for RMNCAH: complementary financing.” The background to this item is that the GFF has been established as a partnership in which multiple financiers contribute complementary financing to a common set of priorities articulated in an Investment Case. Previous Investors Group discussions (particularly GFF/IG1/6 and GFF/IG2/3) have covered different facets of this, including examining resources flows for RMNCAH and indicators for tracking progress on this agenda. As the GFF becomes operational in a larger number of countries, experience is being gained in the practicalities of complementary financing.