Population II stars are metal poor stars, containing about 0.1% metals. These stars can be found in the spherical portion of the galaxy (the halo and the bulge). Often these stars have tipped and elliptical orbits. These stars are relatively old, aged from 2 - 14 billion years. Extreme Population II stars (the most metal poor) are found in the halo and the globular clusters and are the oldest stars. Intermediate Population II stars are located in the bludge and are slightly more metal rich than the extreme Population II stars, but are still far less metal rich than the intermediate Population I stars.

The difference in metal content and age between Population I stars and Population II stars suggests that Population II stars formed early during the formation of the galaxy, when the galaxy contained nearly pure hydrogen and helium. As the Population II stars evolved, they produce metals through fusion. Stellar winds and novae carried these metals into the galaxy. Hence, the younger stars would be metal rich before fusion began.