Caltha novae-zelandiae, commonly known as New Zealand marsh marigold or yellow caltha, is a small (usually 3–5 cm), perennial herbaceous plant belonging to the family Ranunculaceae, that grows in open vegetations in mountainous areas, and is endemic to New Zealand.

The spade-shaped leaves have slender, grooved petioles of up to 10 cm long that form a membranous sheathing base.

The leaf blade is dark green and sometimes has a central blotch or it has bronze markings, are 8-25 × 4–12 mm with two lobes at its base, with an indent at its tip and entire or slightly scalloped edges.

The basal lobes (or appendages) are mostly pressed against the upper surface of the leaf and, almost half as long.

The five to seven pale yellow sepals are 1–3 cm long and 2–3 mm wide, 3-nerved, linear-ovate, widest between the base and half length, and have an acute tip.