Sosa is a former municipality in the western Ore Mountains, in the Erzgebirgskreis, Saxony, Germany.

Sosa lies on both sides of the like-named Sosabach at an elevation of between 550 and 817 m above sea level.

The people originally worked the land; however, from the 18th century onwards, mining gained in importance.

In the second half of the 19th century, mining was diminishing in importance, and many migrated to the Zwickau coalfields.

Development of population figures (31 December): Between 1949 and 1952, the Sosa Reservoir was built.