Literature assessing the quantity and quality of voluntary social and environmental reporting has shown critical reflections regarding the quality and reliability, the (largely) qualitative nature of disclosure with lack of measurability, credibility or comparability, and information being biased and self-laudatory in nature with minimal disclosure of negative information. Among environmentally-sensitive sectors, forest-based industry has a crucial role in global sustainable development, not only because of its unique raw material basis, but also because of the ongoing industry globalization in the emerging and developing countries. The contribution of this study is important in at least two dimensions: first, providing empirical quantitative insight regarding the current patterns in responsibility disclosure of the forest-based sector at a global level; and second, by taking a quantitative approach in investigating determinants of the disclosure. Changing patterns in the economic, environmental and social performance of the forest-based industry were analyzed using the Global Reporting Initiative (GRI) framework, which represents an international cooperative effort to establish sustainability reporting guidelines for voluntary use by organizations worldwide. We seek to shed more light on what are the key responsibility or sustainability issues the global forest companies address, and which of the firm and industry level determinants are significant on the quality of disclosure? Sustainability disclosure of 66 top forest industry companies is first content analyzed based on the GRI framework, after which significance of industry and firm characteristics, including geographic location, business line and financial performance, will be used as testing the determinants influencing the quality and level of disclosure. Based on the content analysis, more emphasis was found to be placed on the environmental and economic responsibility in contrast to areas concerning human rights, labour practices, social and product responsibility in the forestry sector. Main findings from the regression modeling include a significant positive effect from company size on the quality and extent of CR reporting practices in the forest industry; no effect from the financial performance; little regional variation; and illustration of difference in disclosure orientation between integrated forest industry companies and those with more narrowly focused business. From the managerial perspective, in the future, business leaders in the forest industry are expected to adopt a more proactive role not only in reducing the environmental footprint or promoting sustainable forest management, but also in furthering social goals.