Stellaria obtusa is a species of flowering plant in the pink family known by the common names Rocky Mountain chickweed, blunt-sepaled starwort, and obtuse starwort. It is native to western North America, from British Columbia and Alberta to California to Colorado, where it grows in moist areas in forests and on mountain slopes. It is a rhizomatous perennial herb producing a prostrate, creeping, branching stem up to about 20 centimeters long, sometimes forming mats. The oval leaves are up to about a centimeter long and are borne in opposite pairs on the stem. Solitary flowers occur in the leaf axils, each borne on a short pedicel. The small flower has no petals, just four to five blunt-tipped green sepals each a few millimeters long.