| Ayat | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Russia, Kazakhstan |
| Subdivision Type3: | Region |
| Subdivision Name3: | Chelyabinsk Oblast, Kostanay Region |
| Length Km: | 117 |
| Source1: | Confluence of rivers Karataly-Ayat and Archagly-Ayat |
| Mouth: | Karatomar reservoir |
| Mouth Coordinates: | 52.8774°N 62.8346°W |
| Basin Size Km2: | 13300 |
The Ayat (Russian and ba|Аят, Ayat; kk|Аят: Aıat) is a river in Chelyabinsk Oblast, Russia and Kostanay Region, Kazakhstan. Ayat is formed by the confluence of Karataly-Ayat and Archagly-Ayat. The river flows into the Karatomar reservoir, which is drained by the river Tobol. The length of the river is 117 km, with a catchment area of 13,300 km².[1]
Much of the basin is formed by 383 drainless lakes (total area 208 km².). Russian part of the river has a length of 23 km and a watershed area of 8571 km².
The soils of the basin are mostly sandy and loam, occasionally salt. Laboissiere alluvial channels the channel is located in a well defined river valley.
In winter, the river often freezes to the bottom. Freezing was observed 5 times in past 43 years.