The marsh sandpiper (Tringa stagnatilis) is a small wader. It is a rather small shank, and breeds in open grassy steppe and taiga wetlands from easternmost Europe to central Asia.

It resembles a small elegant greenshank, with a long fine bill and very long yellowish legs. Like the greenshank, it is greyish brown in breeding plumage, paler in winter, and has a white wedge up its back that is visible in flight. However, it is more closely related to the common redshank and the wood sandpiper. Together, they form a group of smallish shanks which tend to have red or reddish legs, and in breeding plumage are generally a subdued, light brown above with some darker mottling, with a pattern of somewhat diffuse small brownish spots on the breast and neck. The length is 22–26 cm (8.7–10.2 in), wingspan is 55–59 cm (22–23 in) and weight is 45–120 g (1.6–4.2 oz).