地幔（德语：Erdmantel；英语：mantle；法语：manteau；原于拉丁语：mantellum「斗篷」），**称作地函，位于地壳之下，地核之上，和地壳以莫氏不连续面为界，和地核间则以古氏不连续面为界。厚度约2900公里。化学成分主要是含铁镁的硅酸盐，平均密度是3.3-5.5g/cm。地函含石榴子石，辉石，橄榄石及其他类型的岩石。占地球体积的83%，总质量的68%。由于P波及S波皆可通过地函，故推测地函主要为固体构成。地函可分成地函上部、过渡带及地函下部。

The mantle is a layer inside a terrestrial planet and some other rocky planetary bodies. For a mantle to form, the planetary body must be large enough to have undergone the process of planetary differentiation by density. The mantle lies between the core below and the crust above. The terrestrial planets (Earth, Venus, Mars and Mercury), the Moon, two of Jupiter's moons (Io and Europa) and the asteroid Vesta each have a mantle made of silicate rock. Interpretation of spacecraft data suggests that at least two other moons of Jupiter (Ganymede and Callisto), as well as Titan and Triton each have a mantle made of ice or other solid volatile substances.