Few prior studies investigated the correlation between corporate ownership structure and environmental information disclosure. Using environmental index disclosure in GRI (Global Reporting Initiative) reports of the Korean companies, the study examines the effects of ownership structure on the magnitude of environmental information disclosure. A total of 220 firm-years during 2013-2016 period are analyzed. The empirical results of the study indicate that the institutional and foreign investors’ ownership have positive correlations with environmental information disclosure, while the executives' within board of directors has a negative correlation. The ownership by largest shareholders including those with special interests shows no significant relationship with the environmental information disclosure.