Cost of debt is one of factors that firms consider when making their financing decision. Firms use more debt for their operating business in case of lower debt cost. Therefore, determing the impact factors on cost debt is interested in by firms and scholars. This study uses samples of 313 listed firms on Ho Chi Minh Stock exchange over period 2012 to 2017. The finding is that foreign ownership, state ownership, and financing leverage adversely affect on debt cost, while average 12-month interest positively impacts on the cost of debt.