Board of commissioners in the two-tier system board of Indonesian companies has an important oversight role on behalf on the shareholders. The objective of this study is to examine whether the board effectiveness strengthen the positive association between voluntary disclosure and true firm performance. True firm performance is the amount of firm profitability after taking out the discretionary accruals. Hypothesis testing is carried out using fixed effect data panel regression analysis with 312 firm-year observations in manufacturing industry.  The sample is taken from the Indonesian Stock Exchange listed companies within the period of 2012-2014. The result of this study shows that voluntary disclosure has a nonlinear significant effect on true firm performance. This relationship is strengthened for firms with effective board of commisioners.