Milgrain, also spelled millegrain or millgrain in older British and European usage, is a decorative finishing technique in which the edge of a metal mounting is worked into a continuous line of small raised beads. The term derives from the French mille grains, literally a thousand grains, and describes the visual effect of a closely spaced row of metallic dots running along the boundary of a setting, a bezel, the edge of a shank, or any other defined line in a piece of jewellery. The technique is used both as an ornamental device in its own right and as a means of softening the visual transition between metal and stone, particularly in pavé and bead-set diamond work.

Milgrain is most commonly produced with a milgrain wheel, a small handheld tool with a finely toothed disc that is rolled along the edge of the workpiece under steady pressure, indenting the metal to produce the beaded line. Skilled bench jewellers can also produce milgrain by hand using a beading tool and a steady graving technique, a slower method but one that gives sharper definition on platinum and high-karat gold. The finish became a defining feature of Edwardian and Art Deco jewellery from roughly 1900 to 1935, where it was used extensively on platinum mounts to outline diamond clusters and to articulate the geometry of stepped and tiered designs. It has remained in continuous use since, and has returned to particular prominence in twenty-first-century vintage-revival design.