This research aimed to examine the Impact of Ownership Structure on the relationship between the level of voluntary disclosure and cost of capital on the Egyptian Listed Companies. The sub aims of this research as follows: 1. Examining the relationship between level of voluntary disclosure and cost of capital. 2. Examining the Impact of Ownership Structure on the relationship between level of voluntary disclosure and cost of capital. To achieve this objective, using a multiple linear regression on a sample of 75 Egyptian companies listed on Stock Exchange, at a rate of 42.5% of listed non-financial Egyptian firms, over the period 2014-2016 The most important results of the study included: 1. The research showed that the relationship between voluntary disclosure and cost of capital, cost of equity capital, and cost of debt was not statistically significant at 10% level of significance 2. The research showed that the relationship between the level of voluntary disclosure and costcapital, cost of equity and cost of debt was positive significantwith the ownership structure as an organized variable. 3. The research showed Ownership has a significant negativeeffect on relaion betweenlevel of voluntary disclosure and cost of capital at 10% level of significance. Keywords: Ownership Structure, level of voluntary disclosure, cost of capital, cost of equity capital, and cost of debt capital.