Environmental sustainability performance and its disclosure are not company's primary objectives rather are practices that lift the reputation of company in society. Environmental sustainability disclosure is not mandatory by accounting standards; however, information on environmental sustainability is of interest to various stakeholders for informed decision making. Financial reporting does not provide sufficient information for stakeholders to make an informed decision. It is with a view to addressing this concern that the study investigated the impact of corporate governance on environmental sustainability disclosure of non-financial companies quoted in Nigeria. Ex-post facto research design was adopted for the study. The population was 109 non-financial companies quoted in Nigeria as at 31 December, 2020. Stratified and purposive sampling techniques were used to select a sample of 72 non-financial companies that were in existence for a period of 9 years, 2012 to 2020. Data were extracted from published annual reports of the sampled non-financial companies and validated by certification of external auditors and the Nigerian Stock Exchange. Data were analyzed using descriptive and multiple regression analysis. The study found that the combined effect of corporate governance (CG) had a significant effect on environmental sustainability disclosure (END) (Adj. R 2 = 0.1783, F(6, 641) = 170.58, ρ = 0.00). The separated effects were varied. Board Independence (BOI), Nomination Committee (NOC), and Sustainability Responsibility Committee (SRC) have a positive and significant effect on END (BOI=0.0031, t-test=5.28, ρ = 0.001; NOC=0.1391, t-test=3.50, ρ = 0.008; SRC=0.6165, t-test=6.68, ρ = 0.000). Risk Committee (RIC) and Remuneration Committee (REC) have a positive and insignificant effect on END (RIC=0.0519, t-test=1.61, ρ = 0.147; REC=0.0083, t-test=0.020, ρ = 0.849) while Board Meetings has a negative and insignificant effect on END (BOM=-0.0016, t-test=-0.27, ρ = 0.792). The study concluded that corporate governance enhanced environmental sustainability disclosure of non-financial companies quoted in Nigeria. The study recommended that management should institute sound corporate governance mechanisms, especially a sustainability responsibility committee to enable improved environmental sustainability practices and their disclosure.