Purpose: This paper investigates the effect of corporate board attributes, ownership structure and firm-level characteristics on both corporate mandatory and voluntary disclosure behaviour in annual reports of Libyan firms.Design/methodology/approach: Multivariate regression techniques are used to estimate the effect of corporate board and ownership structures on mandatory and voluntary disclosures of a sample of Libyan firms between 2006 and 2010.Findings: First, we find that board size, board composition, the frequency of board meetings and the presence of an audit committee have an impact on the level of corporate disclosure. Second, this study finds an evidence that director ownership, foreign ownership, government ownership and institutional ownership have a non-linear effect on the level of corporate disclosure. Finally, we find that firm age, liquidity, listing status, industry type and auditor type are positively associated with the level of corporate disclosure.Limitation: Future research could investigate disclosure practices using other channels of corporate disclosure, such as corporate websites. Useful insights may be offered also by future studies by conducting in-depth interviews with corporate managers, directors and owners regarding these issues.Implication: Investors may also rely on such corporate governance characteristics to shape expectations about voluntary and/or mandatory information disclosure. Originality/value: Existing disclosure studies have mainly examined governance and voluntary disclosure relationship in non-listed firms. Our study, therefore, extends, as well as contributes to the existing literature by the examining the governance-disclosure nexus relating to both mandatory and voluntary disclosures in both listed and non-listed firms.