茶黄素（英语：Theaflavin）是存在于红茶中的一种金黄色色素，为茶叶发酵的产物。在生物化学上，茶黄素是一类多酚羟基具茶骈酚酮结构的物质。

因红茶加工烘焙的方法不同，茶黄素的比例可占茶重量的0.5%到2%不等；茶黄素一定程度的影响了茶汤的颜色深浅和口感浓淡差异，是红茶重要的品质指标。

Theaflavin (TF) and its derivatives, known collectively as theaflavins, are antioxidant polyphenols that are formed from the condensation of flavan-3-ols in tea leaves during the enzymatic oxidation (fermentation) of black tea. Theaflavin-3-gallate, theaflavin-3'-gallate, theaflavin-3-3'-digallate are the main theaflavins. Theaflavins are types of thearubigins, and are therefore reddish in color. Epigallocatechin gallate (EGCG) will metabolize into some theaflavins in the liver.