The objective of the study is to assess the determinants of corporate sustainability disclosure among large firms in Kenya. Specific objectives are; to determine the level of corporate sustainability disclosure among large firms in Kenya, to determine the effect of strategic posture on corporate sustainability disclosure among large firms in Kenya, to determine the effect of firm attributes on corporate sustainability disclosure among large firms in Kenya, and to determine the effect of stakeholder attributes on corporate sustainability disclosure among large firms in Kenya. A descriptive research design was employed so as to accomplish the study objectives by finding out if the independent variables determine the level of corporate sustainability disclosure among large Kenyan firms. The study’s target population comprised Kenyan firms listed by the Kenya Revenue Authority (KRA) in its large tax payers category. The KRA large taxpayers list is used as a basis for definition of large firms in Kenya. The study collected primary data to meet the research objectives. Primary data was collected using a questionnaire. Data analysis was carried out on the collected quantitative data using descriptive and inferential statistics. Pearson R correlation was used to measure strength and the direction of linear relationship between variables. Multiple regression model was fitted to the data in order to test the effect of the independent variables on the dependent variable. Diagnostic tests were also considered to test the model for linearity, heteroscedasticity, multicollinearity, and normality. Strategic posture, firm attributes, and stakeholder attributes determine corporate sustainability disclosure among large firms in Kenyan. Results of the study revealed positive and significant effect of strategic posture, firm attributes, stakeholder attributes on corporate sustainability disclosure. This implies that there is need for large firms to improve on their levels of governance disclosure in comparison with environmental disclosure. Large firms ought to strategize measures geared towards strategic position, internal and organization culture should be geared on disclosing information which would aid minimizing cost of accessing required information. Thirdly, there is need for coherent communication amongst stakeholders to eliminate pressures which may jeopardize quality of information shared publicly.