Glossopetalon spinescens is a species of flowering shrub in the family Crossosomataceae known by the common names spiny greasebush, spiny greasewood and Nevada greasewood. It is native to the western United States and northern Mexico, where it grows in mountainous habitats, often on limestone substrates. This shrub forms a dense, erect clump of many thin, branching, thorny stems approaching 2 metres (6.6 ft) in maximum height. The green oval leaves are less than two centimeters long. Small white-petalled flowers appear in the leaf axils. The fruit is a single or double follicle a few millimeters wide.