The study investigated the effects of dietary taurine (Tau) and methionine (Met) supplementation on growth, tissue taurine concentrations and taurine synthesis of giant grouper (Epinephelus lanceolatus) fed a diet with high plant protein. The basal diet containing soy protein concentrate (replaced 50% fishmeal protein) was supplemented with 0.25, 0.5, 1% Met or 0.1%, 0.2%, 0.3% Tau, respectively. Total of seven experimental diets were each fed to triplicate groups of fish (initial weight: 18.13 ± 0.05 g) in a recirculation system for 8 weeks. Weight gain of fish fed diets with 0.25% Met or 0.1%-0.3% Tau were higher (p<0.05) than that of fish fed the Met or Tau free control diet. Whole body, muscle, and hepatic Tau concentrations increased with the increment of dietary Tau levels. However, the tissue Tau concentrations were not affected by the dietary Met levels. Hepatic cysteinesulfinate decarboxylase gene expression was higher in fish fed diets with 0.25% and 0.5% Met than that in fish fed the control diet. Results indicated that dietary taurine and methionine supplementation can enhance growth performance of giant grouper fed the diet with high level of plant protein. Supplementation of methionine in diet enhances Tau synthesis gene expression but not enhances the tissue taurine concentration, suggesting that the ability of taurine synthesis in grouper is limited.