The study was conducted to examine the effect of heat treatment of green tea waste (GTW) on rumen degradability, apparent digestibility, and plasma metabolites in Black Bengal goat based on in vitro and in vivo studies. The in vitro incubation was performed with autoclaved, oven, and freeze-dried GTW, whereas animal study was conducted using 12 Black-Bengal goats in a 3 Â 3 Latin-square design. Goats were fed a total-mixed-ration without (control) or with the partial replacement of soybean meal and barley with 50 g/kg dry matter (DM) of either oven-dried or autoclaved GTW. Heat treatments reduced ether extract and tannins concentration but increased the effective DM and crude protein (CP) degradability of GTW. The highest values of in vitro volatile fatty acid concentration, molar proportion of propionate, ammonia-nitrogen concentration, and cumulative gas production were observed for oven-dried GTW among the tested GTW. Dietary treatment did not alter the DM intake, but apparent CP digestibility and retained nitrogen (N) were increased in goats fed control or oven-dried GTW incorporated diets. Feeding autoclaved GTW diet increased the urinary and fecal N excretion in goats. In contrast, plasma glucose concentration was highest in goats fed control or oven-dried GTW diet. In conclusion, oven drying could be a practical approach to increase protein digestibility and retained N in goats.