This paper examines the role of businesses in the tax system. In addition to being taxed directly, businesses act as withholding agents and remitters of tax on behalf of others. Yet the share of tax revenue that businesses remit to governments outside of direct tax liabilities is under-studied. This paper develops two measures of the contribution of businesses to the tax system and applies both these measures for 24 OECD countries. The results show that businesses play an important role in the tax system, both as taxpayers and as remitters of tax. However, care should be taken in interpreting any measure of the business tax burden, which must be understood against the backdrop of economic incidence. This paper highlights that the economic incidence, or burden, of a tax is not necessarily borne by the person on whom the tax is imposed under legal statute, but may be passed on to others in the economy, whether it be owners of capital, workers or consumers.