The Sary su (also Sary-Sû and Sarsa) is a river in central Kazakhstan. It arises above Atasu and flows generally westward to Kzyl-Dzhar where it turns southwestard past Birlestik and Zhanabas, then heading ever-more southerly it ends at a series of small lakes (often dry) called the Ozera Segiz. In former times it was a tributary of the Syr Darya, and it may still provide some subsurface flow, but the surface flow disappears more than 100 km from the Syr Darya. The name sary su means yellow water in Turkic languages.