<p>Characterizing flavour-related metabolites of <i>Camellia sinensis</i> (L.) Kuntze is essential for enhancing tea quality and understanding the biochemical foundations of its distinctive taste and aroma. Metabolites like catechins, polyphenols and flavonoids not only contribute to the sensory appeal of tea but also offer multiple health benefits. Comprehensive profiling of these metabolites in indigenous tea germplasm – an underexplored genetic resource –offers valuable insights into their genetic diversity and potential application in breeding programs to develop new cultivars with tailored flavour profiles. In this context, a study was conducted to characterize flavour-related metabolites, including pigment, total polyphenols, catechins and their derivatives, caffeine, tannins and antioxidant activity, across 169 ancient tea germplasm of Assam. Comparative analysis among Assam, China and Cambod-type like varieties revealed significant differences, with F-values highly significant at 0.001. Quantification using RP-HPLC identified catechins, caffeines and gallic acid in the following order of abundance: (-)-Epigallocatechingallate &gt; Caffeine &gt; (-)-Epicatechin &gt; (-)-Epicatechingallate &gt; Gallic acids &gt; (-)- Epigallocatechins &gt; ( +)- Catechins, with Epigallocatechingallate as the predominant contributor. Notably, Cambod-type germplasm exhibited higher metabolite concentrations compared to Assam and China types. High heritability (h²b) values for all measured traits indicated minimal environmental influence. Additionally, a strong correlation between pigment, catechins and their derivatives, caffeine likely explains the astringent and bitterness properties of tea. Moreover, high antioxidant activity can boost tea’s market value. The findings could not only enhance the understanding of tea’s flavour profiles but also pave the way for development of higher-quality tea and improved breeding material for future research programmes.</p>