Bay-chested Warbling-Finch
Castanozoster thoracicus
- Least concern
- Card rarity: Common
- Birds

The bay-chested warbling finch is a species of bird in the family Thraupidae. It is endemic to southeastern Brazil. Its natural habitats are temperate forests and subtropical or tropical moist montane forests.
Classification
- Class
- Aves
- Order
- Passeriformes
- Family
- Thraupidae
- Genus
- Castanozoster